thiourea

H302: Harmful if swallowed [Warning Acute toxicity, oral]

H351: Suspected of causing cancer [Warning Carcinogenicity]

H361d ***: Suspected of damaging the unborn child [Warning Reproductive toxicity]

H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P203, P264, P270, P273, P280, P301+P317, P318, P330, P391, P405, and P501 (click each P-code to see the statement)

This chemical does not meet GHS hazard criteria for 0.3% (2 of 710) of reports.

H302 (98.7%): Harmful if swallowed [Warning Acute toxicity, oral]

H351 (99.6%): Suspected of causing cancer [Warning Carcinogenicity]

H361 (84.4%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H361d (15.1%): Suspected of damaging the unborn child [Warning Reproductive toxicity]

H411 (99.7%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

Aggregated GHS information provided per 710 reports by companies from 27 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 2 of 710 reports by companies.

There are 26 notifications provided by 708 of 710 reports by companies with hazard statement code(s).

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H317: May cause an allergic skin reaction [Warning Sensitization, Skin]

H320: Causes eye irritation [Warning Serious eye damage/eye irritation]

H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H361: Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

H401: Toxic to aquatic life [Hazardous to the aquatic environment, acute hazard]

P203, P260, P261, P264, P264+P265, P270, P271, P272, P273, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P318, P319, P321, P330, P333+P317, P337+P317, P362+P364, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

P203, P260, P261, P264, P264+P265, P270, P271, P272, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P318, P319, P321, P330, P333+P317, P337+P317, P362+P364, P403+P233, P405, and P501 (click each P-code to see the statement)

H361d: Suspected of damaging the unborn child [Warning Reproductive toxicity]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

P203, P261, P264, P270, P272, P273, P280, P301+P317, P302+P352, P318, P321, P330, P332+P317, P333+P317, P362+P364, P391, P405, and P501 (click each P-code to see the statement)

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention .

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Induce vomiting (ONLY IN CONSCIOUS PERSONS!). Refer for medical attention .

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. IMMEDIATELY call a physician and be prepared to transport the victim to a hospital even if no symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital.

OTHER: Since this chemical is a known or suspected carcinogen you should contact a physician for advice regarding the possible long term health effects and potential recommendation for medical monitoring. Recommendations from the physician will depend upon the specific compound, its chemical, physical and toxicity properties, the exposure level, length of exposure, and the route of exposure. (NTP, 1992)

Fire Extinguishing Agents: Small fires: dry chemical, CO2, water spray or foam; large fires: water spray, fog or foam. (USCG, 1999)

Use water spray, foam, powder, carbon dioxide. In case of fire: keep drums, etc., cool by spraying with water.

Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.

Wear self-contained breathing appartus for fire-fighting if necessary.

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids.

SPILL: Increase the immediate precautionary measure distance, in the downwind direction, as necessary.

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Evacuate danger area! Consult an expert! Personal protection: chemical protection suit and particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Do NOT wash away into sewer. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.

Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

Use personal protective equipment. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust.

Sludge was treated with 5% aq soln of thiourea, sand & portland cement at pH 12.5. Leaching test of resulting concrete showed that dissolved concn of mercury, cadmium,lead, copper, & arsenic were far below regulation levels.

For more Cleanup Methods (Complete) data for THIOUREA (6 total), please visit the HSDB record page.

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U219, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A potential candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.

The following wastewater treatment technology has been investigated for thiourea: Concentration process: Biological treatment.

PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... Summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/

For more Disposal Methods (Complete) data for THIOUREA (8 total), please visit the HSDB record page.

In the case of the precursor /to aminothiazole/, thiourea, particular attention should be given to the hazard of skin absorption by the provision of protective clothing and adequate sanitary facilities incl showers.

PRECAUTIONS FOR "CARCINOGENS": Smoking, drinking, eating, storage of food or of food & beverage containers or utensils, & the application of cosmetics should be prohibited in any laboratory. All personnel should remove gloves, if worn, after completion of procedures in which carcinogens have been used. They should ... wash ... hands, preferably using dispensers of liq detergent, & rinse ... thoroughly. Consideration should be given to appropriate methods for cleaning the skin, depending on nature of the contaminant. No standard procedure can be recommended, but the use of organic solvents should be avoided. Safety pipettes should be used for all pipetting. /Chemical Carcinogens/

PRECAUTIONS FOR "CARCINOGENS": ... Operations connected with synth & purification ... should be carried out under well-ventilated hood. Analytical procedures ... should be carried out with care & vapors evolved during ... procedures should be removed. ... Expert advice should be obtained before existing fume cupboards are used ... & when new fume cupboards are installed. It is desirable that there be means for decreasing the rate of air extraction, so that carcinogenic powders can be handled without ... powder being blown around the hood. Glove boxes should be kept under negative air pressure. Air changes should be adequate, so that concn of vapors of volatile carcinogens will not occur. /Chemical Carcinogens/

PRECAUTIONS FOR "CARCINOGENS": Vertical laminar-flow biological safety cabinets may be used for containment of in vitro procedures ... provided that the exhaust air flow is sufficient to provide an inward air flow at the face opening of the cabinet, & contaminated air plenums that are under positive pressure are leak-tight. Horizontal laminar-flow hoods or safety cabinets, where filtered air is blown across the working area towards the operator, should never be used. ... Each cabinet or fume cupboard to be used ... should be tested before work is begun (eg, with fume bomb) & label fixed to it, giving date of test & avg air-flow measured. This test should be repeated periodically & after any structural changes. /Chemical Carcinogens/

For more Preventive Measures (Complete) data for THIOUREA (11 total), please visit the HSDB record page.

Neutralizing Agents for Acids and Caustics: Neutralize with six normal hydrochloric acid. (USCG, 1999)

Separated from acids, food and feedstuffs, acrolein and oxidants. Cool. Well closed. Keep in a well-ventilated room.

Keep container tightly closed in a dry and well-ventilated place. Handle and store in inert gas. Storage class (TRGS 510): Non Combustible Solids.

Thiourea is packed in polyethylene bags (less than or equal to 50 kg) or in folding containers (less than or equal to 1500 kg). Bags and containers must be kept tightly closed, and in a cool, dry place. The contents must be protected from the action of light.

PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practicable to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired. ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/

0.38 [mg/m3]

4.1 [mg/m3]

25 [mg/m3]

sensitization of skin (SH); photosentization (SP); carcinogen category: 3

Evaporation at 20 °C is negligible; a harmful concentration of airborne particles can, however, be reached quickly.

The substance is irritating to the eyes.

Repeated or prolonged contact may cause skin sensitization. The substance may have effects on the thyroid. This substance is possibly carcinogenic to humans.

Wear self-contained positive pressure breathing apparatus and full protective clothing. (USCG, 1999)

Wear rubber gloves & gas mask.

PRECAUTIONS FOR "CARCINOGENS": ... Dispensers of liq detergent /should be available./ ... In animal laboratory, personnel should remove their outdoor clothes & wear protective suits (preferably disposable, one-piece & close-fitting at ankles & wrists), gloves, hair covering & overshoes. ... Clothing should be changed daily but ... discarded immediately if obvious contamination occurs ... /also,/ workers should shower immediately. In chemical laboratory, gloves & gowns should always be worn ... however, gloves should not be assumed to provide full protection. Carefully fitted masks or respirators may be necessary when working with particulates or gases, & disposable plastic aprons might provide addnl protection. If gowns are of distinctive color, this is a reminder that they should not be worn outside of lab. /Chemical Carcinogens/

NO open flames.

AVOID ALL CONTACT! IN ALL CASES CONSULT A DOCTOR!

Avoid inhalation of dust and mist. Use local exhaust or breathing protection.

Protective gloves. Protective clothing.

Wear face shield or eye protection in combination with breathing protection if powder.

Do not eat, drink, or smoke during work. Wash hands before eating.

Thiourea appears as white or off-white crystals or powder. Sinks and mixes with water. (USCG, 1999)

Other Solid; Dry Powder; Large Crystals

White or off-white crystals or powder; [CAMEO]

WHITE CRYSTALS OR POWDER.

White or off-white crystals or powder.

White solid which crystallizes in a rhombic bipyramidal structure

White lustrous crystals

Three functional groups - amino, imino, and thiol

Odorless

Sublimes in vacuum at 302-320 °F (NTP, 1992)

Decomposes at boiling point

Sublimes in vacuum at 302-320 °F

349 to 352 °F (NTP, 1992)

176-178 °C

349-352 °F

10 to 50 mg/mL at 68 °F (NTP, 1992)

In water, 1.42X10+5 mg/L at 25 °C

Soluble in water at 25 °C: 1 part in 11

Aqueous solubility data in g/L: 0.4676 at 0 °C; 85.07 at 10 °C; 117.5 at 20 °C; 133.9 at 25 °C; 167.4 at 30 °C; 235.5 at 40 °C; 415.2 at 60 °C, 579.8 at 80 °C; 704.1 at 100 °C

Soluble in alcohol; sparingly soluble in ether.

For more Solubility (Complete) data for THIOUREA (6 total), please visit the HSDB record page.

142 mg/mL at 25 °C

Solubility in water: moderate

>11.4 [ug/mL] (The mean of the results at pH 7.4)

1.405 at 68 °F (USCG, 1999) - Denser than water; will sink

1.405 g/cu cm at 25 °C

1.4 g/cm³

1.405 at 68 °F

1.405 @25 °C

0.0028 [mmHg]

1.41X10-7 mm Hg at 25 °C

log Kow = -1.08

-2.38/-0.95

When heated to decomposition it emits very toxic fumes of nitroxides and sulfoxides.

Heat of combustion at constant volume is -1482.2 kJ/mol (-19.47 kJ/g), and at constant pressure -1485.6 kJ/mol (-19.52 kJ/g)

1.0404X10-2 N/m at 454.15 K

Acrylaldehyde is very reactive & will polymerize rapidly, accelerating to violence, in contact with strong acid or basic catalysts. ... Exposure to weakly acidic conditions (nitrous fumes, sulfur dioxide, carbon dioxide), some hydrolysable salts, or thiourea will also cause exothermic & violent polymerization.

pK-value not determinable according to OECD guideline no. 112 with the titration method at 24 °C (forms no OH or H ions)

Three functional groups - amino, imino, and thiol ... can react as the tautomeric iminothiol ... forms calthrates ... can be alkylated and acylated, and reacts with aldehydes and ketones.

Neutral reaction; forms addition compound with metallic salts

Water soluble.

Amides and Imides

Sulfides, Organic

THIOUREA is a white crystalline material or powder, toxic, carcinogenic. When heated to decomposition it emits very toxic fumes of oxides of sulfur and oxides of nitrogen. Violent exothermic polymerization reaction with acrylaldehyde (acrolein) [MCA SD-85, 1961], violent decomposition of the reaction product with hydrogen peroxide and nitric acid [Bjorklund G. H. et al., Trans. R. Soc. Can.,1950, 44, p. 28], spontaneous explosion upon grinding with potassium chlorate [Soothill, D., Safety Management, 1992, 8(6), p. 11].

The solid peroxide produced by action of hydrogen peroxide & nitric acid on thiourea (& possibly a hydrogen peroxidate of thiourea dioxide) decomposed violently on drying in air, with evolution of sulfur dioxide & free sulfur.

Reacts with various sulfhydryl-oxidizing agents; complexes & adducts with organic cmpd, protein & certain hydrocarbons.

Acrolein polymerizes with release of heat on contact with thiourea.

Incompatible with acrylaldehyde; hydrogen peroxide; nitric acid.

IDENTIFICATION AND USE: Thiourea occurs as white, lustrous crystals or flaky solids. It is not registered for current pesticide use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses. It has many uses including for photography and photocopying papers, organic synthesis of dyes, drugs, and hair preparations, rubber accelerators, analytical reagents, amino resins, mold inhibitors, flame retardants for textiles, peptizing agents, pesticides, chelating agents, and as a reagent for bismuth and selenite ions. Other uses are as an additive for slurry explosives, as a viscosity stabilizer for polymer solutions (e.g., in drilling muds), and as a mobility buffer in petroleum extraction. The removal of mercury from wastewater from chlorine-alkali electrolysis and gold and silver extraction from minerals are also of economic importance. Thiourea has been identified as being used in hydraulic fracturing as a corrosion inhibitor. HUMAN EXPOSURE AND TOXICITY: The primary routes of potential human exposure to thiourea are inhalation and dermal contact. The greatest risk of potential exposure exists for workers involved in the production or use of thiourea. Thiourea has been identified as a sensitizer in people suffering from photosensitivity. It may also cause depression of bone marrow with anemia, leukopenia and thrombocytopenia. Thiourea was used in former times as a thyroid depressant in patients with hyperthyroidism. A daily dose of <15 mg (<0.2 mg/kg body weight per day for a 70-kg adult) in adults did not lead to measurable depression of the thyroid gland function, while a dose of 70 mg/day (about 1.0 mg/kg body weight per day) produced a remission of hyperthyroidism. ANIMAL STUDIES: Thiourea is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity in experimental animals. When administered in the drinking water, thiourea induced thyroid adenomas and carcinomas in rats of both sexes and squamous cell carcinomas of the Zymbal gland in male rats. When administered in the diet, thiourea induced hepatocellular adenomas in rats and hepatomas in rainbow trout. When injected intraperitoneally and administered in drinking water, thiourea induced squamous cell carcinomas and mixed cell sarcomas in the Zymbal gland of rats of both sexes. Thiourea also causes development and reproductive abnormalities. In studies with pregnant ewes administered 50 mg thiourea/kg body weight daily for 2, 4, or 6 months, abortion, stillbirth, birth of weak/low-weight lambs, dystokia, and retention of placenta were common features. The severity of changes was dependent upon the stage of gestation when hypothyroidism was induced. High dose thiourea severely inhibited thyroid function in rat pups, significantly depressed body growth, and retarded development of the acoustic startle response. At the low dose there was a significant reduction in growth, but no effect on acquisition of acoustic startle reflex. Thiourea has shown genotoxicity. When tested at a dose range of 1X10-2 to 1X10-5 M, was found to be weakly active in causing unscheduled DNA synthesis. In hepatocytes, thiourea elicited a linear increase in DNA repair replication in the concentration range tested (5-25 mM). In V79 cells, thiourea (10-40 mM) significantly increased the frequency of 8-azaguanine-resistant mutants. ECOTOXICITY: Treatment with 0.03% thiourea via immersion for 21 days induced hypothyroidism (thyroid hormone depletion) as evidenced by significantly reduced serum T(3) levels in the catfish, Clarias gariepinus. Thiourea-treated males had narrowed seminiferous lobules with fewer spermatozoa in testis, very little or no secretory fluid, reduced protein and sialic acid levels in seminal vesicles when compared to controls; accompanied by reduction in serum and tissue levels of testosterone (T) and 11-ketotestosterone (11-KT), a potent male specific androgen in fish. There were physiological and histological signs of recovery after 21 days such as reappearance of spermatozoa and partial restoration of 11-KT and T levels. In yearling rainbow trout, Salmo gairdneri, thiourea treatment resulted in depression of gill Na+/K+-ATPase activity in sea water (in 0.5% thiourea) or delayed adaptive increase in ATPase activity (in 0.3% thiourea) following sea water entry as compared to control fish.

The Human Health Assessment Group in EPA's Office of Health and Environmental Assessment has evaluated thiourea for carcinogenicity. According to their analysis, the weight-of-evidence for thiourea is group B2, which is based on sufficient evidence in animals. No data available in humans. As a group B2 chemical, thiourea is considered a probable human carcinogen..

Evaluation: There is inadequate evidence in humans for the carcinogenicity of thiourea. There is limited evidence in experimental animals for the carcinogenicity of thiourea. Overall evaluation: Thiourea is not classifiable as to its carcinogenicity to humans (Group 3).

Thiourea: reasonably anticipated to be a human carcinogen.

Thiourea

Group 3: Not classifiable as to its carcinogenicity to humans

Volume Sup 7: Overall Evaluations of Carcinogenicity: An Updating of IARC Monographs Volumes 1 to 42, 1987; 440 pages; ISBN 92-832-1411-0 (out of print)

Volume 79: (2001) Some Thyrotropic Agents

3, not classifiable as to its carcinogenicity to humans. (L135)

The substance can be absorbed into the body by inhalation of its aerosol and by ingestion.

Redness.

Dermatotoxin - PACD (photoallergic contact dermatitis).

NTP Carcinogen - Reasonably anticipated to be a human carcinogen.

LC50 (rat) > 900 mg/m3/4h

LD50 Rat oral differs from strain to strain: 125 to 640 mg/kg in the domestic rat, 1860 mg/kg in the Norway rat.

LD50 Rat oral 20 mg/kg

LD50 Rat ip 436 mg/kg

LD50 Mouse Oral approx. 1000 mg/kg bw

For more Non-Human Toxicity Values (Complete) data for THIOUREA (9 total), please visit the HSDB record page.

Changes of TSH-producing cells in the pituitary and thyroid expression of the growth factors, transforming growth factor alpha (TGF alpha) and epidermal growth factor receptor (EGFR), as well as cyclin D1, were investigated immunohistochemically in order to clarify their contribution to the enhancing effects of excess vitamin A (VA) on thyroidal carcinogenesis induced by thiourea (TU). Male rats were allocated to 4 groups, control, TU, VA, and TU + VA, respectively, receiving no treatment, water containing 0.2% TU, diet containing 0.1% VA, and both for 10 or 19 weeks after a single s.c. injection of DHPN (N-bis(2-hydroxypropyl)nitrosamine) (2800 mg/kg) for initiation. Immunohistochemistry using antibodies against TSH demonstrated enlargement of TSH-producing cells in the TU + VA group as compared to the TU group, supporting our conclusion that enhanced TSH stimulation is mainly responsible for promoting the effects of excess VA. Since the expression of TGF alpha, EGFR, and cyclin D1 in thyroid proliferative lesions did not exhibit any differences between the TU and TU + VA groups in the present study, these factors are unlikely to participate in VA enhancement of carcinogenesis.

In our previous investigation, which focused on two-stage carcinogenicity in the thyroid, rats were administered N-bis(2-hydroxypropyl)nitrosamine (DHPN), followed by thiourea (TU) over an experimental period of 19 weeks. Simultaneous treatment with a high level of vitamin A (VA) enhanced the induction of proliferative lesions that originated from the thyroidal follicular epithelium. To examine whether hormone synthesis in the thyroid could be inhibited by simultaneous treatment with a large amount of VA and TU, all of the rats were initially given a single subcutaneous injection of 2,800 mg DHPN/kg followed by a supply of 0% TU + 0% VA (DHPN only, control group), 0.2% TU in their drinking water (DHPN/TU group), 0.1% VA in their diet (DHPN/VA group), or 0.2% TU + 0.1% VA (DHPN/TU + VA group) during an experimental period of 4 weeks. Results obtained indicate that the iodine uptake and organification, namely iodination of tyrosine residue in thyroglobulin, of the thyroid, were significantly decreased in the DHPN/TU group compared to the DHPN control group. The variation in these values was attributable to the inhibitory effect of TU upon thyroid hormone synthesis. Results obtained from the DHPN/TU + VA and DHPN/TU groups were comparable. Therefore, the possibility that modification of hormone synthesis contributes to the enhancing effect of simultaneous treatment with a large amount of VA on thyroidal tumor induction by TU is considered to be very minimal.

Time course changes in serum TSH and quantitative data for thyroid proliferative lesions in male F344 rats administered N-bis(2-hydroxypropyl)nitrosamine (DHPN: 2000 mg/kg body weight, single s.c. injection) followed by 0.1% thiourea (TU), were assessed at weeks 1, 2, 4, 8, 12 and 16 of treatment. The serum T4 level in the TU group was markedly decreased at week 1 and remained significantly lowered throughout the experiment. Serum TSH levels, in contrast, were elevated up to a peak at around week 4 with a return to the normal range at week 12. Thyroid weights in the TU group were increased significantly in a treatment period-dependent manner. Histopathologically, marked hypertrophy of thyroid follicular cells occurred at the early stage of TU treatment. Proliferative lesions, such as hyperplasia and adenomas, occurred from weeks 2 and 4, respectively, and increased with the later treatment period. The cell proliferative activity of follicular cells, assessed by BrdU incorporation, was high until week 2, but then returned to normal. The initially appearing hyperplasias and adenomas were characterized by marked proliferation but this also greatly decreased at later stages when TSH was no longer elevated. The results of our study thus suggest that a high serum TSH level plays an important role in the early phase of thyroid tumorigenesis and 8 weeks treatment with test substances is sufficient for detection of thyroid tumor promoter potential in two-stage thyroid carcinogenesis models.

To evaluate the effects of phenobarbital (PB) and thiourea (TU), alone or in combination, on proliferative lesions of the liver, thyroid and lung, male F344 rats initiated with 2000 mg/kg body weight N-bis(2-hydroxypropyl) nitrosamine (DHPN) were given diet and/or drinking water containing 0% PB/TU (group 1), 1000 ppm PB (group 2), 0.1% TU (group 3) and 500 ppm PB and 0.05% TU (group 4), from weeks 2 to 20 for 19 weeks. Group 4 showed remarkable increases in the number of hepatocellular altered foci per animal, the values being superior to the averages of groups 2 and 3. The number of thyroid proliferative lesions per animal was highest in group 3 and lowest in group 2. Lung proliferative lesions were induced in all groups, but no modifying influence on their development was evident in the combined group. The present results indicate that combined administration of PB and TU exerts synergistic enhancing effects on hepatocarcinogenesis.

For more Interactions (Complete) data for THIOUREA (24 total), please visit the HSDB record page.

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on the left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/

/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/

/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W TKO /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

PRECAUTIONS FOR "CARCINOGENS": ... In relation specifically to cancer hazards, there are at present no health monitoring methods that may ensure the early detection of preneoplastic lesions or lesions which may prelude them. Whenever medical surveillance is indicated, in particular when exposure to a carcinogen has occurred, ad hoc decisions should be taken concerning additional tests that might become useful or mandatory. /Chemical Carcinogens/

/HUMAN EXPOSURE STUDIES/ In an early study with hyperthyroid patients (n = 12), it was shown that a dose of 15 mg (about 0.2 mg/kg body weight per day for a 70-kg person) daily for 10-12 weeks was insufficient to depress thyroid activity, as judged by the concentrations of serum precipitable iodine, while a dose of 70 mg daily (1.0 mg/kg body weight per day) in conjunction with iodine solution produced a remission in hyperthyroidism.

/SIGNS AND SYMPTOMS/ Elevated temperature was observed almost immediately after commencement of the therapy and regressed upon its termination. Both attacks of feverishness, which occur within 7-14 days after the onset of the therapy, and skin reactions have been attributed to sensitization.

/SIGNS AND SYMPTOMS/ There are reports on disorders of workers coming into contact with thiourea during the course of, for example, maintenance of machinery or packing, without providing any details as to exposure levels. The symptoms observed were typical of hypothyroidism, as evidenced by facial edema, hypotonia, bradycardia, electrocardiograph alterations associated with reduced basal metabolism, constipation, flatulence, polyuria, and granulocytopenia, accompanied by lymphocytosis and monocytosis. The first perturbations of the blood count were observed after 5-6 months of exposure, and the highest incidence of the symptoms was evident in those workers who had been in contact with the chemical for 5-15 years...

/SIGNS AND SYMPTOMS/ In the manufacture of rubber, irritant contact dermatitis may occur from a variety of acids, alkalis, detergents, and solvents used in the process. Allergic contact dermatitis occurs not infrequently and is almost always due to an organic accelerator or antioxidant. While the list of potential sensitizing accelerators and antioxidants is enormous, common allergens include ... thioureas. /Thioureas/

For more Human Toxicity Excerpts (Complete) data for THIOUREA (16 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Experimental pulmonary edema was induced in adult male Sprague-Dawley rats injected intraperitoneally with thiourea at doses of 3, 6, or 10 mg/kg body weight. Induction of pulmonary edema was observed by a significant increase in the ratio of lung weight to body weight in all three groups of experimental rats. An increase in plasma calcium and a decrease in plasma copper and ceruloplasmin were observed in the rats in the two highest dose groups.

/LABORATORY ANIMALS: Acute Exposure/ When rabbit skin was exposed to 0.5 g of thiourea for a period of 4 hr, the substance was tolerated without reaction.

/LABORATORY ANIMALS: Acute Exposure/ A 24-hr exposure to undiluted thiourea applied to the intact and abraded skin of rabbits resulted in mild to marked erythema with a slight degree of edema.

/LABORATORY ANIMALS: Acute Exposure/ Screening tests on rabbit corneas have shown moderate toxicity when thiourea was introduced into corneal stroma.

For more Non-Human Toxicity Excerpts (Complete) data for THIOUREA (57 total), please visit the HSDB record page.

EPA has released the first beta version (version 0.5) of the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The beta version of the iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays; Click on the "Chemical Explorer" button on the tool bar to see the data./[USEPA; ICSS Dashboard Application; Available from, as of December 8, 2014: http://actor.epa.gov/dashboard/]

EC50; Species: Scenedesmus abundans (Green algae) 10+4 cells/mL; Conditions: freshwater, static, 22 °C; Concentration: 4800 ug/L for 96 hr; Effect: inhibition of cell growth /99.5% purity/

EC50; Species: Scenedesmus abundans (Green algae) 10+4 cells/mL; Conditions: freshwater, static, 22 °C; Concentration: 4800 ug/L for 96 hr; Effect: inhibition of cell growth /99.5% purity/

LC50; Species: Daphnia magna (Water flea) age <24 hr; Conditions: freshwater, static, 20 °C, pH 8.2, hardness 250 mg/L CaCO3, dissolved oxygen >6.5 mg/L; Concentration: 9000 ug/L for 48 hr (95% confidence interval: 5600-18000 ug/L) />99% purity/

/AQUATIC SPECIES/ /Thiourea-induced thyroid hormone depletion /was used/ ... to understand the influence of thyroid hormones on testicular recrudescence of the air-breathing catfish, Clarias gariepinus. Treatment with 0.03% thiourea via immersion for 21 days induced hypothyroidism (thyroid hormone depletion) as evidenced by significantly reduced serum T(3) levels. Thiourea-treated males had narrowed seminiferous lobules with fewer spermatozoa in testis, very little or no secretory fluid, reduced protein and sialic acid levels in seminal vesicles when compared to controls. The histological changes were accompanied by reduction in serum and tissue levels of testosterone (T) and 11-ketotestosterone (11-KT), a potent male specific androgen in fish. Qualitative changes in the localization of catfish gonadotropin-releasing hormone (cfGnRH) and luteinizing hormone (LH, heterologous system) revealed a reduction in the distribution of immunoreactive neuronal cells and fibers in thyroid depleted fish. Interestingly, thiourea-withdrawal group showed physiological and histological signs of recovery after 21 days such as reappearance of spermatozoa and partial restoration of 11-KT and T levels. These data demonstrate that thyroid hormones play a significant role in testicular function of catfish. The mechanism of action includes modulating sex steroids either directly or through the hypothalamo (GnRH)-hypophyseal (LH) axis.

/AQUATIC SPECIES/ Exposure of yearling rainbow trout, /Oncorhynchus mykiss/, to either 0.3% or 0.5% thiourea in fresh water or subsequently in dilute sea water; impaired osmoregulatory performance in both media. Thiourea treatment resulted in depression of gill Na+/K+-ATPase activtiy in sea water (in 0.5% thiourea) or delayed adaptive increase in ATPase actvity (in 0.3% thiourea) following sea water entry as compared to control fish. Plasma Na+ and Cl- levels decreased in fresh water fish and increased in sea water acclimated fish exposed to thiourea. T4 replacement did not abolish these effects. Neither did thiourea treatment depress circulating levels of total T4, and the observed effects were probably associated with thiourea toxicity in extrathyroidal sites. The effectiveness of thiourea to block thyroid function in fish is discussed.

/AQUATIC SPECIES/ Methylmercury (CH3Hg(II)) was measured in various tissues and whole body of sheepshead minnows, Cyprinodon variegatus, following exposure to 100 ng/L methylmercury chloride (CH3HgCl) alone or in combination with one of the organic compounds cysteine (CH3Hg-Cys), thiourea (CH3Hg-Thu), or thioglycolate (CH3Hg-Thg). Overall, the CH3Hg(II) concentration in sheepshead minnows in all the treatments increased with time and was significantly different from the unspiked controls after 24 hr. Addition of the organic compounds increased the bioavailability of CH3Hg(II) in the whole body of the fish after 72 hr. In particular, the CH3Hg(II) concentration after CH3Hg-Thg and CH3Hg-Thu exposure was, respectively, approximately 1.3- and 1.6- fold higher than with CH3HgCl exposure. A composite of the CH3Hg(II) concentrations in the visceral organs (gill, liver, and intestine) highlighted the effect of the organic compounds, where concentrations in all mercury-thiolate treatments were significantly higher than CH3HgCl alone after 72 hr. The most dramatic changes in the different tissues measured were observed in the liver, where the CH3Hg(II) concentrations in the sulfur treatments were significantly higher than the CH3HgCl treatment after 72 hr. The results of this study suggest that the CH3Hg-thiolate complexes were bioavailable to sheepshead minnows and effectively induced CH3Hg(II) uptake in tissues at environmentally realistic CH3HgCl concentrations.

/OTHER TERRESTRIAL SPECIES/ The effect of thiourea (applied topically, in different concentrations, to the eggs and all the nymphal instars, and to adults also by feeding) on the red cotton-bug Dysdercus similis was studied. The eggs were severely affected (i.e. mortality was high), while the nymphal instars showed an adverse effect on ecdysis and adults which emerged from the treated last nymphal instar were characterized by high mortality, abnormal behaviour and reduced fecundity and viability. They were also smaller, weaker and morphologically abnormal compared with the controls and were differently coloured. They were likewise unable to reproduce, owing to atrophy of the gonads. The ovaries contained a large number of immature, pathological oocytes with degenerating follicular epithelium, which was thin with a regular outline in the early stages, but later became multilayered, with pyknotic nuclei, and displayed active destruction of glycoproteins and lipoproteins. Fibrogenesis and thickening of the tunica propria were clearly discernible. Although treated females were kept together with untreated males, the two showed no signs of being attracted to one another and displayed no mating behaviour, although some females showed a very low degree of ovulation. Only a few survived the Ist nymphal instar and none survived up to adult emergence, despite being kept under normal laboratory conditions.

/OTHER TERRESTRIAL SPECIES/ Urea (U), hydroxyurea (HU), and thiourea (TU), in various concentrations, were added to chemically defined plant tissue culture medium on which Meloidogyne javanica /root-knot nematode/ was reared on excised tomato roots. Concentrations as low as 3 ppm HU or 12 ppm TU inhibited nematode maturation by 70-90% 4 weeks after inoculation, and the coenocytes in the parasitized tissue were poorly developed. Gall weight was also inhibited by 50% in cultures treated with 3 and 6 ppm HU. However, exposing juveniles of M. javanica and Tylenchulus semipenetrans /citrus nematode/ or juveniles and adults of Pratylenchus thornei /Thorne's root-lesion nematode/ to increasing concentrations of HU or TU, up to 100 ppm, was not lethal. These two urea derivatives still inhibited nematode maturation when the infected region of the root was not in direct contact with the chemicals. Therefore, we suggest that these urea derivatives inhibit nematode development by affecting the plant metabolism essential to coenocyte formation, an occurrence similar to the hypersensitive reaction in a naturally resistant plant.

The substance is toxic to aquatic organisms.

Thiourea's production and use in the production of thiourea dioxide for wool and textile processing, in ore leaching, in photography and photocopying-diazo papers, as a catalyst in fumaric acid synthesis and as an intermediate to manufacture dyes, drugs, hair preparations and other chemicals may result in its release to the environment through various waste streams. Its use in hydraulic fracturing fluids will result in its direct release to the environment. Thiourea has been detected in laburnum shrubs (Laburnum anagyroides) and is a natural metabolite of the fungi Verticillium alboatrum and Bortrylius cinerea. If released to air, a vapor pressure of 1.41X10-7 mm Hg at 25 °C indicates thiourea will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase thiourea will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 9 hours. Particulate-phase thiourea will be removed from the atmosphere by wet and dry deposition. Thiourea weakly absorbs at wavelengths 290 to 310 nm and, therefore, may be susceptible to direct photolysis by sunlight. If released to soil, thiourea is expected to have very high mobility based upon a measured Koc range of 7-36. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 1.1X10-13 atm-cu m/mole. Thiourea is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Utilizing the Japanese MITI test, 2.6% of the Theoretical BOD was reached in 2 weeks indicating that thiourea is not readily biodegradable. Elevated thiourea concentrations may be toxic to microorganisms and inhibit biodegradation. Thiourea may be susceptible to direct photolysis on soil surfaces exposed to sunlight. If released into water, thiourea is not expected to adsorb to suspended solids and sediment in water based upon the estimated Koc. Die-away studies using fresh water and seawater from observed slow but continuous biodegradation of thiourea over the incubation period of 85 days. The die-away tests demonstrate that thiourea serves as nitrogen source for degrading microorganisms with thiourea more easily biodegraded in nitrogen-limited environments. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. A measured BCF of <2 suggests bioconcentration in aquatic organisms is low. Thiourea is stable to hydrolysis at environmentally relevant pH. Thiourea may be susceptible to direct and indirect photolysis at water surfaces exposed to sunlight. Occupational exposure to thiourea may occur via dermal contact with this compound at workplaces where thiourea is produced or used. The general population may be exposed to thiourea via dermal contact with consumer products containing thiourea. (SRC)

Thiourea has been detected but not quantified in laburnum shrubs (Laburnum anagyroides) and is a natural metabolite of the fungi Verticillium alboatrum and Bortrylius cinerea(1).

Thiourea's production and use in the production of thiourea dioxide for wool and textile processing, in ore leaching, in photography and photocopying-diazo papers, as a catalyst in fumaric acid synthesis and as an intermediate to manufacture dyes, drugs, hair preparations and other chemicals(1,2) may result in its release to the environment through various waste streams(SRC). Its use in hydraulic fracturing fluids(3) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), a measured Koc range of 7-36(2,3) indicates that thiourea is expected to have very high mobility in soil(SRC). Volatilization of thiourea from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.1X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 1.41X10-7 mm Hg(4), and its water solubility, 1.34X10+5 mg/L(5). Thiourea is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Utilizing the Japanese MITI test, 2.6% of the Theoretical BOD was reached in 2 weeks indicating that thiourea is not readily biodegradable(6). However, water, sediment and soil degradation studies have indicated that thiourea is biodegradable(2,7). In aerobic batch laboratory microcosm experiments, thiourea half-lives of 12.8 days (basic soil) and 18.7 days (acid soil) were determined(2,7), however, no abiotic controls were performed, and removal of thiourea was attributed mainly to biotic processes(2). Elevated thiourea concentrations may be toxic to microorganisms and inhibit biodegradation(2,7).

AQUATIC FATE: Based on a classification scheme(1), a measured Koc range of 7-36(2,3) indicates that thiourea is not expected to adsorb to suspended solids and sediment in water(SRC). Volatilization from water surfaces is not expected(4) based upon an estimated Henry's Law constant of 1.1X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 1.41X10-7 mm Hg(5) and water solubility, 1.34X10+5 mg/L(6). According to a classification scheme(7), a measured BCF of <2 in carp (Cyprinus carpio)(8) suggests the potential for bioconcentration in aquatic organisms is low. Die-away studies using freash and saltwater observed slow but continuous degradation of thiourea over the incubation period of 85 days (maximum 9% within the first 8 days, maximum 68% at the end of observation based on carbon dioxide production)(9); in sediment samples, 40-70% degradation was observed(9). The die-away tests demonstrate that thiourea serves as nitrogen source for degrading microorganisms with thiourea more easily biodegraded in nitrogen-limited environments(2). Thiourea may be degraded slowly in water by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in natural water is estimated to be 206 days(SRC), calculated from its rate constant of 3.9X10+9 L/mol-sec(10). Thiourea is hydrolytically stable(9).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), thiourea, which has a vapor pressure of 1.41X10-7 mm Hg at 25 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase thiourea is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 9 hours(SRC), calculated from its rate constant of 4.2X10-11 cu cm/molecule-sec at 25 °C(SRC) determined using a structure estimation method(3). Particulate-phase thiourea may be removed from the air by wet and dry deposition(SRC). In methanol solution, the ultraviolet absorption spectrum of thiourea shows weak absorption from 290 to 310 nm with no absorption above 310 nm(4), and therefore, may be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: Thiourea, present at 30 mg/L, reached 2.6% of its theoretical BOD in two weeks using an activated sludge inoculum at 100 mg/L in the Japanese MITI test(1). Using a modified MITI test (OECD 301C guideline) and a 34-day incubation period, thiourea was also found to be not readily biodegradable(2). Four separate OECD 302A (SCAS TEST, inherent biodegradation) studies observed thiourea removal of 45-97% over 13-84 days test durations in which the inoculum was very slowly adapted to increasing thiourea concentrations prior to incubation(2). Using a low initial concentration of thiourea (50 ug/L), thiourea had a 5-day CO2 evolution of 17% using an activated inoculum and a German GSF Biodegradation Test(3,4). A 27-day Zahn-Wellens Test resulted in no degradation(4). Using the Warburg technique, a concentration of 500 mg/L thiourea was found to be toxic or very poorly oxidized by various activated sludges(5). In studies using sterilized versus non-sterilized soils, microorganisms were believed to take an active part in the transformation of thiourea, although high initial concentration of thiourea suppressed microflora activity for a period of up to 60 days(6).

AEROBIC: The aerobic biodegradability of thiourea was tested in water and sediment samples of the Elbe River (including its estuary) and the western reaches of the Baltic Sea(1). In all water samples from the Elbe estuary, very slow but continuous degradation of thiourea was observed over the incubation period of 85 days (maximum 9% within the first 8 days, maximum 68% at the end of observation; based on carbon dioxide production)(1). In sediment samples, 40-70% degradation was observed(1). In samples taken from the Baltic Sea, biodegradation varied widely between 50 and 87% in water and between 28 and 72% in sediment(1). The Elbe River and Baltic Sea die-away tests demonstrate that thiourea serves as nitrogen source for degrading microorganisms with thiourea more easily biodegraded in nitrogen-limited environments(2). In aerobic batch laboratory microcosm experiments, thiourea half-lives of 12.8 days (basic soil) and 18.7 days (acid soil) were determined(1,2), however, no abiotic controls were performed, and removal of thiourea was attributed mainly to biotic processes, assuming abiotic mechanisms to be of minor importance(1). In a soil microorganism degradation study, 22% of an initial thiourea (1.5 g/L) was degraded within 1 week and 96% within 15 weeks of incubation(1); thiourea concentrations exceeding 7.6 g/L inhibited microbial transformation(1). After applying thiourea concentrations of 5 and 200 mg/L to soil in a plant growth test, a marked increase in mineral nitrogen was observed within 4 weeks of incubation, which was explained by primary degradation of thiourea(1).

ANAEROBIC: Very little degradation of thiourea was observed in a solution medium inoculated with sewage sludge(1).

The rate constant for the vapor-phase reaction of thiourea with photochemically-produced hydroxyl radicals has been estimated as 4.2X10-11 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 9 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the reaction of hydroxyl radicals in aqueous solutions is 3.9X10+9 L/mol-sec(2); this corresponds to an aquatic half-life of 206 days at an aquatic concentration of 1X10-17 hydroxyl radicals per liter(3). In methanol solution, the ultraviolet absorption spectrum of thiourea shows weak absorption from 290 to 310 nm with no absorption above 310 nm(4), and therefore, may be susceptible to direct photolysis by sunlight(SRC). The GSF Test for photochemical degradation resulted in a 0.23% thiourea degradation(5). Thiourea, adsorbed on silica gel and irradiated with light >290 nm, resulted in 4.7% degradation(6). Measurable degradation was observed in a sterilized soil study, although the mechanism for the degradation was not studied(7); it was possibly due to photodegradation(8). Thiourea is hydrolytically stable, as measured according to OECD Guideline A-79.74D(9). Aqueous hydrolysis tests conducted at 70 °C and pH 3, pH 7 and pH 11 observed zero degradation after 6 days(10).

BCF values of <0.2 and <2 were measured in fish for thiourea at concentrations of 3 and 0.3 ppm, respectively, using carp (Cyprinus carpio) which were exposed over an 6-week period(1). According to a classification scheme(2), these BCF values suggest the potential for bioconcentration in aquatic organisms is low(SRC). A 24-hour static test BCF of 54 was measured in Alga chlorella(3).

Using OECD Guideline 106 (Adsorption - Desorption Using a Batch Equilibrium Method), thiourea had measured Koc values of 28, 26 and 36 in Alfisol (neutral loam), Spodosol (acidic sandy) and Entisol (slightly basic loam) soils respectively(1). A measured Koc value of 7 has also been reported(2). According to a classification scheme(3), these Koc values suggest that thiourea is expected to have very high mobility in soil. In soil column adsorption studies using five Eurosoils, thiourea was used as a tracer due to its minimum interaction with the solid matrix and had Kd values of 0.00 in all five soils(4).

The Henry's Law constant for thiourea is estimated as 1.1X10-13 atm-cu m/mole(SRC), derived from its vapor pressure, 1.41X10-7 mm Hg(1), and water solubility, 1.34X10+5 mg/L(2). This Henry's Law constant indicates that thiourea is expected to be essentially nonvolatile from water surfaces(3). Thiourea's estimated Henry's Law constant indicates that volatilization from moist soil surfaces is not expected to occur(SRC). Thiourea is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

Thiourea is listed in the USEPA Toxics Release Inventory (TRI) of possible compounds released from electric power plants burning coal or oil(1).

According to the 2012 TSCA Inventory Update Reporting data, 5 reporting facilities estimate the number of persons reasonably likely to be exposed during the manufacturing, processing, or use of thiourea in the United States may be as low as 10-24 workers and as high as 100-499 workers per plant; the data may be greatly underestimated due to confidential business information (CBI) or unknown values(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 37,571 workers (10,969 of these were female) were potentially exposed to thiourea in the US(1). Occupational exposure to thiourea may occur via dermal contact with this compound at workplaces where thiourea is produced or used. The general population may be exposed to thiourea via dermal contact with consumer products containing thiourea(SRC). Consumer exposure to thiourea can occur from the metabolism of thiourea-based pharmaceuticals(2). There is possible dermal contact with blueprint paper(2). Metal polish can contain up to 10% thiourea; if silver cutlery is not washed thoroughly after dipping in the cleaner, thiourea could be ingested(2). Dermal contact from the cleaning process could be relevant for those occupationally exposed(2).

In a Russian thiourea manufacturing factory, reported air concentrations of thiourea were in the range 0.6-12 mg/cu m(1); in the middle of the production hall, the air concentration was 3.9 mg/cu m, and concentrations around loading and cleaning were higher (9.0 mg/cu m)(1). In 1988-1991, workplace measurements (12 personal and stationary samples) from the production and packing of thiourea at the German manufacturer gave an average air concentration (thiourea in total dust) of 0.085 mg/cu m (maximum 0.32 mg/cu m)(1).

Thiourea concentration in the urine of workers occupationally exposed to carbon disulfide was 37% higher than in a control group(1).

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U219, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

A potential candidate for rotary kiln incineration at a temperature range of 820 to 1,600 °C and residence times of seconds for liquids and gases, and hours for solids. A potential candidate for fluidized bed incineration at a temperature range of 450 to 980 °C and residence times of seconds for liquids and gases, and longer for solids.

The following wastewater treatment technology has been investigated for thiourea: Concentration process: Biological treatment.

PRECAUTIONS FOR "CARCINOGENS": There is no universal method of disposal that has been proved satisfactory for all carcinogenic compounds & specific methods of chem destruction ... published have not been tested on all kinds of carcinogen-containing waste. ... Summary of avail methods & recommendations ... /given/ must be treated as guide only. /Chemical Carcinogens/

For more Disposal Methods (Complete) data for THIOUREA (8 total), please visit the HSDB record page.

Marine pollutant. Do not transport with food and feedstuffs.

Symbol: Xn, N; R: 22-40-51/53-63; S: (2)-36/37-61

UN Hazard Class: 6.1; UN Pack Group: III