selenium dioxide

H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]

H314 (10.2%): Causes severe skin burns and eye damage [Danger Skin corrosion/irritation]

H318 (10.2%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H331 (89.8%): Toxic if inhaled [Danger Acute toxicity, inhalation]

H373 (100%): May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

H400 (52.3%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

H410 (100%): Very toxic to aquatic life with long lasting effects [Warning Hazardous to the aquatic environment, long-term hazard]

P260, P261, P264, P264+P265, P270, P271, P273, P280, P301+P316, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P317, P319, P321, P330, P363, P391, P403+P233, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 264 reports by companies from 21 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

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.

H301: Toxic if swallowed [Danger Acute toxicity, oral]

H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

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]

P260, P264, P264+P265, P270, P280, P301+P316, P305+P351+P338, P308+P316, P319, P321, P330, P337+P317, P405, and P501 (click each P-code to see the statement)

H300: Fatal if swallowed [Danger Acute toxicity, oral]

H371: May cause damage to organs [Warning Specific target organ toxicity, single exposure]

Fresh air, rest. Half-upright position. Artificial respiration may be needed. Refer for medical attention.

Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

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

Rinse mouth. Do NOT induce vomiting. Refer for medical attention .

Consult physician after all exposures to this compound.

INHALATION: remove victim to fresh air; give oxygen if needed.

INGESTION: induce vomiting; follow with gastric lavage and saline cathartics.

EYES: flush immediately and thoroughly with water.

SKIN: flush with water. (USCG, 1999)

Excerpt from ERG Guide 151 [Substances - Toxic (Non-Combustible)]:

SMALL FIRE: Dry chemical, CO2 or water spray.

LARGE FIRE: Water spray, fog or regular foam. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal. Avoid aiming straight or solid streams directly onto the product.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

In case of fire in the surroundings, use appropriate extinguishing media.

If material on fire or involved in fire: Extinguish fire using agent suitable for type of surrounding fire. Material itself does not burn or burns with difficulty. Keep run-off water out of sewers and water sources. /Selenium compound, solid, nos/

Personnel protection: Wear appropriate chemical protective clothing. Wear positive pressure self-contained breathing apparatus when fighting fires involving this material. /Selenium compound, solid, nos/

Excerpt from ERG Guide 151 [Substances - Toxic (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! Sweep spilled substance into covered containers. Carefully collect remainder. Then store and dispose of according to local regulations. Personal protection: complete protective clothing including self-contained breathing apparatus. Do NOT let this chemical enter the environment.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number D010; U204, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

All sources of selenium oxide or fumes should be fitted with exhaust ventilation systems with an air speed of at least 30 m/min. ... smoking, eating and drinking at the workplace should be prohibited, and messrooms and sanitary facilities including showers and locker rooms should be provided ... wherever possible, operations should be mechanized, automated or provided with remote control.

Non-impervious clothing which becomes contaminated with selenium, sodium selenite, sodium selenate, selenium dioxide or liquids containing these compounds should be removed promptly and not reworn until the contaminant is removed from the clothing.

Skin Exposure: If selenium or its inorganic compounds get on the skin, immediately wash the contaminated skin. If selenium, sodium selenite, sodium selenate, or selenium dioxide soak through the clothing, remove the clothing immediately and wash the skin. If irritation persists after washing, get medical attention.

Smoking, eating, & drinking at the workplace should be prohibited, & messrooms & sanitary facilities incl showers & locker rooms should be provided at a point distant from exposure areas. Wherever possible, operations should be mechanized, automated, or provided with remote control. /selenium oxide/

For more Preventive Measures (Complete) data for SELENIUM DIOXIDE (13 total), please visit the HSDB record page.

Excerpt from ERG Guide 151 [Substances - Toxic (Non-Combustible)]:

Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS. For solids, prevent dust cloud and avoid inhalation of dust. (ERG, 2024)

Separated from food and feedstuffs. Dry.

0.02 [mg/m3], as Se, inhalable fraction[German Research Foundation (DFG)]

0.84 [mg/m3]

2.2 [mg/m3]

13 [mg/m3]

0.2 [mg/m3], as Se

1.0 [mg/m3], as Se

8 hr Time Weighted Avg (TWA): 0.2 mg/cu m. /Selenium and compounds, as Se/

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded. /Selenium and compounds, as Se/

0.2 mg/m

(as Se, inhalable fraction): 0.02 mg/m

Chronic Oral: 0.005 mg/kg/day (L134)

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

The substance is corrosive to the eyes, skin and respiratory tract. Inhalation may cause lung oedema. The substance may cause effects on the eyes. This may result in allergic-type reaction of the eyelids (rose eye). Medical observation is indicated.

Repeated or prolonged contact may cause skin sensitization. The substance may have effects on the respiratory tract, gastrointestinal tract, central nervous system and liver. This may result in nasal irritation, persistent garlic odour, stomach pain, nervousness and liver impairment.

OCCUPATIONAL VALUES FOR SELENIUM (Class W, oxides, hydroxides, carbides, and elemental Se. Class D, all compounds except those given for W) [Table#1969]

This compound is highly toxic if inhaled or ingested. Dust mask; rubber gloves; protective clothing (USCG, 1999)

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

All sources of selenium oxide or fumes should be fitted with exhaust ventilation systems with an air speed of at lease 30 m/min. /Selenium compounds/

... Dispensing & weighing /selenium dioxide/ powder can be carried out in efficient fume cupboards wearing gloves, whereas cleaning ... electrostatic precipitators & ducting containing red fume mixt of selenium & selenium dioxide can only be done /with/ ... completely impervious suits supplied by air lines.

Wear appropriate personal protective clothing to prevent skin contact. /Selenium/

For more Personal Protective Equipment (PPE) (Complete) data for SELENIUM DIOXIDE (8 total), please visit the HSDB record page.

PREVENT DISPERSION OF DUST! STRICT HYGIENE!

Use local exhaust or breathing protection.

Protective gloves. Protective clothing.

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

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

Selenium dioxide appears as a white or creamy-white volatile lustrous crystal or crystalline powder with a pungent sour smell. Melting point 340 deg C. Density 3.954 g / cm3. Toxic by ingestion and inhalation.

White or yellowish-white to slightly reddish, lustrous, crystalline powder or needles. [HSDB]

LUSTROUS WHITE HYGROSCOPIC CRYSTALS OR POWDER. ITS YELLOWISH GREEN VAPOUR HAS A PUNGENT SOUR SMELL.

Lustrous tetragonal needles; yellowish green vapor

White or yellowish-white to slightly reddish, lustrous, crystalline powder or needles.

Vapor has a pungent sour smell

Rotten radishes.

Acidic taste; leaves a burning sensation.

599 °F at 760 mmHg (sublimes) (USCG, 1999)

340 °C under pressure

Soluble in concentrated sulfuric acid

Solubility (parts/100 parts solvent): 10.16 in methanol at 11.8 °C; 6.67 in 93% ethanol at 14 °C; 4.35 in acetone at 15.3 °C; 1.11 in acetic acid at 13.9 °C

In water, 400 g/L at 20 °C

264 g/100 g water at 22 °C

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

Solubility in water, g/100ml at 20 °C: 40

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

3.954 at 15 °C/15 °C

Density (at 15 °C): 3.95 g/cm³

3.95 @25 °C

12.5 mm Hg at 70 °C; 20.2 mm Hg at 94 °C; 39.0 mm Hg at 181 °C; 760 mm Hg at 315 °C; 848 mm Hg at 320 °C

Vapor pressure, kPa at 70 °C: 1.65

Stable to light and heat.

When heated to decomposition ... emits toxic fumes of /selenium/.

In presence of water will corrode most metals

... Soluble in water forming selenic acid, a corrosive material. ...

0.0002 mg/cu m

Air: 2.0 ppm

Index of refraction: less than 1.76 at 20 °C/D

Dipole moment: 2.62 debye

Dissolves in water to form selenious acid

Electron affinity: 1.823 eV

Heat of formation: at 25 °C -238.5 kJ/mol

For more Other Experimental Properties (Complete) data for SELENIUM DIOXIDE (13 total), please visit the HSDB record page.

Other Classes -> Other Inorganic Compounds

In presence of water will corrode most metals (USCG, 1999). Readily soluble in water forming selenious (selenous) acid.

Oxidizing Agents, Strong

Strong Oxidizing Agent

Inorganic oxidizing agents, such as SELENIUM DIOXIDE, react with reducing agents to generate heat and products that may be flammable, combustible, or otherwise reactive. SELENIUM DIOXIDE reacts with water, particularly hot water, to give selenious (selenous) acid, a weak acid that is corrosive. Stable to light and heat. Rapidly absorbs dry hydrogen fluoride, hydrogen chloride, hydrogen bromide to form the corresponding selenium oxohalide. A good oxidizing agent. Reacts oxidatively with ammonia to form dinitrogen gas and selenium [Merck]. Oxidizes many organic substances.

Do not use metal and acid to reduce selenium compounds. This will produce toxic gaseous hydrogen selenide. /Selenium compounds/

Acids, strong oxidizers, chromium trioxide, potassium bromate. /Selenium/

Selenium readily substitutes for sulfur in biomolecules and in many biochemical reactions, especially when the concentration of selenium is high and the concentration of sulfur is low. Inactivation of the sulfhydryl enzymes necessary for oxidative reactions in cellular respiration, through effects on mitochondrial and microsomal electron transport, might contribute to acute selenium toxicity. Selenomethionine (a common organic selenium compound) also appears to randomly substitute for methionine in protein synthesis. This substitution may affect the structure and functionability of the protein, for example, by altering disulfide bridges. Inorganic forms of selenium appear to react with tissue thiols by redox catalysis, resulting in formation of reactive oxygen species and causing damage by oxidative stress. (L619)

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

Chronic oral exposure to high concentrations of selenium compounds can produce a disease called selenosis. The major signs of selenosis are hair loss, nail brittleness, and neurological abnormalities (such as numbness and other odd sensations in the extremities). Animal studies have shown that selenium may also affect sperm production and the female reproductive cycle. (L619)

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

Oral (L619) ; inhalation (L619) ; dermal (L619)

Burning sensation. Cough. Laboured breathing. Sore throat. Shortness of breath. Symptoms may be delayed.

Redness. Pain. Skin burns. Blisters.

Redness. Pain. Severe deep burns.

Abdominal pain. Burning sensation. Sore throat. Shock or collapse.

Short-term oral exposure to high concentrations of selenium may cause nausea, vomiting, and diarrhea. Brief exposures to high levels of elemental selenium or selenium dioxide in air can result in respiratory tract irritation, bronchitis, difficulty breathing, and stomach pains. Longer-term exposure to either of these air-borne forms can cause respiratory irritation, bronchial spasms, and coughing. (L619)

Neurotoxin - Other CNS neurotoxin

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

Reproductive Toxin - A chemical that is toxic to the reproductive system, including defects in the progeny and injury to male or female reproductive function. Reproductive toxicity includes developmental effects. See Guidelines for Reproductive Toxicity Risk Assessment.

Dermatotoxin - Skin burns.

Skin Sensitizer - An agent that can induce an allergic reaction in the skin.

Toxic Pneumonitis - Inflammation of the lungs induced by inhalation of metal fumes or toxic gases and vapors.

LD50: 23 mg/kg (Oral, Mouse) (L727)

LD50: 4 mg/kg (Dermal, Rabbit) (L727)

LD50: 3.6 mg/kg (Intraperitoneal, Rat) (L727)

LD50: 9 mg/kg (Intravenous, Mouse) (L727)

LD50: 4 mg/kg (Subcutaneous, Rabbit) (L727)

LD50 Mouse (male) oral 16 mg/kg/day

LD50 Rat oral 48 mg/kg/day

LD50 Rabbit subcutaneous 4 mg/kg

Acute toxicity tests showed that selenium dioxide (SeO2) was a strong antagonist against mercuric chloride toxicity in goldfish (Carassius auratus). Paradoxically, whole body accumulations of total mercury (Hg) were significantly increased with the admin of selenium (Se).

The chemopreventive efficacies of selenate, selenite, selenium dioxide, selenomethionine and selenocystine were examined during the promotion phase of carcinogenesis in the 7,12-dimethylbenz(a)anthracene-induced mammary tumor model in rats. Each agent was added to the diet of a final concentration of 3 ppm selenium. In general, there was no significant difference in the potency of these five selenium compounds in inhibiting the development of mammary tumors. The interaction of vitamin E (500 ppm) with either selenite or selenomethionine was further characterized in a second carcinogenesis study. Results of this experiment suggested that vitamin E enhanced the protective effect of selenite but not that of selenomethionine. In an attempt to explore the synergistic mechanism of selenium and vitamin E, the effects of these two agents on mitogen-induced blastogenesis and natural killer cytotoxic activity were also investigated. No consistent changes in these in vitro immune functions were detected resulting from supranutritional feeding of either selenite or vitamin E or both. ...

Studies of lipid peroxidation induced by nickel in experimental animals are reviewed. Male Sprague-Dawley rats injected subcutaneously with nickel chloride show significantly increased lipoperoxidation (as indicated by the presence of thiobarbituric-acid (TAB) chromogens) in the liver, kidney, and lung and dose related increases in hepatotoxicity (as measured by serum aspartate-aminotransferase). ... When pretreated with ... selenium dioxide ..., followed by 500 ug/kg nickel-chloride, the increase of TBA chromogens in rat kidney homogenates is partially suppressed by selenium dioxide. ...

The effects of selenium on cadmium toxicokinetics and on the ability of cadmium to induce metallothionein, a metal-binding protein that is thought to confer tolerance to cadmium toxicity /is determined/. To assess the acute protective effects of selenium, male Wistar (WFr) rats were given selenium (as SeO2; 10 umol/kg, sc) at -24, and +24 hr relative to cadmium (as CdCl2; 45 umol/kg, sc). Over a 14-day period this dose of cadmium killed 6 out of 10 rats, while 100% of the cadmium-treated rats given concurrent selenium treatments survived. The acute increases in testicular weight that were seen with cadmium, indicative of edematous damage, were also prevented by concurrent selenium treatments.

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 as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on 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. /Selenium and Related Compounds/

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 necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for shock and treat if necessary ... . Monitor for pulmonary edema and treat if necessary ... . Treat seizures 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. Administer activated charcoal ... . /Selenium and Related Compounds/

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 if necessary ... . Start IV administration of D5W /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. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Selenium and Related Compounds/

Emergency and supportive measures. Maintain an open airway and assist ventilation if necessary. Administer supplemental oxygen. Treat coma, convulsions, bronchospasm, hypotension, and pulmonary edema if they occur. Since hypotension is often multifactorial, evaluate and optimize volume status, peripheral vascular resistance, and myocardial contractility. Observe for at least 6 hours after exposure. ... /Selenium/

Decontamination: Inhalation. Immediately remove the victim from exposure and give supplemental oxygen if available. Skin and eyes. Remove contaminated clothing and wash exposed skin with soap and copious water. Irrigate exposed eyes with copious tepid water or saline. Ingestion. Ingestion of elemental selenium or selenium salts does not usually benefit from GI decontamination. In light of the risk of severe corrosive GI injury, gastric lavage plus activated charcoal may be of value for ingestion s of selenious acid seen within 1 hour. Invitro experiments indicate that vitamin C can reduce selenium salts to elemental selenium, which poorly absorbed. Its use has not been studied in vivo, but oral or nasogastric administration of several grams of ascorbic acid has been recommended. /Selenium/

Those workers who develop garlic odor of breath should be temporarily removed from work with selenium. 10 days is usually sufficient for garlic breath to disappear. Workers who develop an allergy to selenium dioxide have to be removed permanently from work with selenium or any of Its compounds. /Selenium compounds/

/SIGNS AND SYMPTOMS/ Long-term Exposure: Prolonged exposure to selenium, sodium selenite, sodium selenate, or selenium dioxide may cause paleness, coated tongue, stomach disorders, nervousness, metallic taste and a garlic odor of the breath. ... Prolonged skin contact with selenium oxide or selenium oxychloride may cause skin sensitization.

/SIGNS AND SYMPTOMS/ Short-term Exposure: Inhalation of large quantities of selenium dioxide ... may cause severe breathing difficulties which may not appear for several hours after exposure. Skin contact with selenium dioxide ... may cause skin burns. Skin exposure to selenium dioxide dust may cause a skin rash. Splashes of selenium dioxide may cause eye irritation. Selenium dioxide dust may cause "rose eye" an allergy of the eyelids in which they may become puffy.

/SIGNS AND SYMPTOMS/ ... Selenium dioxide ... caused skin burns and dermatitis. The compound caused excruciating pain when it penetrated under the free edge of the fingernails. It also could cause conjunctivitis and, eventually, an allergic type reaction of the eyes in workers exposed to the dust.

/SIGNS AND SYMPTOMS/ Selenium dioxide is more than a primary irritant, it causes extremely painful burns on the skin which, however, always heal without a scar. Theoretically, the selenium dioxide powder itself does not burn the skin (and if dropped on to the skin should be immediately brushed off dry). However, in practice, in the industrial environment, there is sufficient moisture on the skin from sweating to be taken up by this white solid to form a sticky solution of selenious acid within seconds, or at the most, minutes, of coming into contact with the skin.

For more Human Toxicity Excerpts (Complete) data for SELENIUM DIOXIDE (17 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ ... The toxic effects of respiratory exposure to selenium dioxide (SeO2) /were examined/ under conditions similar to those that occur in industry, i.e., heating of selenium ion. In acute studies, white rats were exposed to air concentrations of selenium dioxide of 0.15 - 0.6 mg/L, and all rats died within one-half to 4 hr. Morphological examination of the organs revealed that intraalveolar and perivascular edema occurred in the lungs, and hemorrhages and degenerative changes in the liver, kidney, and heart. In 4 additional studies, all rats survived 4 hr when exposed to doses of 0.09, 0.06-0.07, or 0.03-0.04 mg selenium dioxide/L, but all rats exposed to the highest dose (equal to 5-5.2 mg/kg body weight) died within 24 hr.

/LABORATORY ANIMALS: Acute Exposure/ Pulmonary function was assessed in non-sensitized male guinea pigs (206-445 g) before and after intratracheal (ITr) treatment with saline or selenium (Se, 0.06 mg/100 g body weight) as selenium dioxide or seleno-L-methionine. Pulmonary functional parameters such as the respiratory rate (f), tidal volume (TV), dynamic lung compliance (Cdynl) and lung resistance (Rl) were determined using the respiratory flow (F) signal and the transpulmonary signal obtained via the intrapleural pressure (P) from the animal. Although, pulmonary dysfunction was observable with exposure to two different Se compounds, the selenium dioxide-induced changes in f and Rl were significant (P < 0.05). Treatment with seleno-L-methionine did not result in alteration of any of the parameters significantly. Results indicated that acute intratracheal selenium dioxide exposure affects respiration precipitated by a significantly decreased f and an increased Rl unlike after seleno-L-methionine. The Cdynl did not change significantly after treatment with either of the two Se compounds. Comparing the immediate effects of the two different Se compounds on respiration, acute intratracheal selenium dioxide exposure was found to be more detrimental to pulmonary function than seleno-L-methionine.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ This study was undertaken to investigate the effects of selenium dioxide (SeO2) on rat blood and femoral bone-marrow oxidant mechanisms. Treatment with SeO2, 67 microg Se/kg i.p. daily for 14 days, significantly decreased lipid peroxidation and the concentrations of Fe in serum and bone marrow. The concentrations of Se in serum and bone-marrow cells were significantly increased after SeO2 treatment. The activities of glutathione peroxidase (GPx) in blood and bone-marrow cells were markedly increased. The levels of oxyhemoglobin in blood were significantly increased, while the concentrations of methemoglobin were decreased after SeO2 administration. The fragility of erythrocytes membranes was significantly decreased in SeO2-treated rats compared to controls. Data suggest that treatment with a low dose of SeO2 may provide antioxidant nutrients to blood and bone marrow.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ ... The toxic effects of respiratory exposure to selenium dioxide (SeO2) /were examined/ under conditions similar to those that occur in industry, i.e., heating of selenium ion. ... In a series of long-term studies, rats were exposed to repeated doses of selenium dioxide at 0.01-0.03, 0.006-0.009, or 0.003-0.005 mg/L for 6 hr, every other day, for one month. The lowest dose did not produce any effects on body weight or on the blood picture, and all the rats survived. Histological examination revealed degenerative changes in the liver, renal tubules, dystrophy of heart muscle, and hyperaemia and hypertrophy of the splenic pulp. At the dose of 0.006-0.009 mg/L, all the rats but one died within 27-33 days. For the first 2 weeks, there was no difference in body weight between the exposed and unexposed control rats but, during the last 2 weeks, the exposed rats lost body weight and all but one of the exposed rats died. The histopathological changes consisted of multiple necrosis and degeneration in the liver and myocardial fibres, and involvement of renal tubules. In the third group of rats, which was exposed to 0.01-0.03 mg/L, the animals showed respiratory distress, weight loss, and, in 3 rats, anemia. All the rats died between days 8 and 18 of exposure. In the liver, kidneys, myocardium, and spleen, the changes observed were similar to those seen at lower doses, but more pronounced. Moreover, lung edema similar to that noted in the acute exposure studies was seen.

For more Non-Human Toxicity Excerpts (Complete) data for SELENIUM DIOXIDE (14 total), please visit the HSDB record page.

EC50; Species: Anabaena flosaquae (Blue-Green Algae); Conditions: freshwater, static, 20 °C; Concentration: 4800 ug/L for 3 days (95% confidence interval: 3200-10000 ug/L); Effect: decreased population biomass

EC50; Species: Chlorella sp. (Green algae); Conditions: freshwater, static, 20 °C; Concentration: 800 ug/L for 3 days (95% confidence interval: 320-1000 ug/L); Effect: decreased population biomass

EC50; Species: Microcystis aeruginosa (Blue-Green algae); Conditions: freshwater, static, 20 °C; Concentration: 7200 ug/L for 3 days (95% confidence interval: 3200-10000 ug/L); Effect: decreased population biomass

EC50; Species: Pseudokirchneriella subcapitata (Green algae); Conditions: freshwater, static, 20 °C; Concentration: 1200 ug/L for 3 days (95% confidence interval: 1000-3200 ug/L); Effect: decreased population biomass

For more Ecotoxicity Values (Complete) data for SELENIUM DIOXIDE (43 total), please visit the HSDB record page.

/PLANTS/ The feasibility of using selenite ion (selenium dioxide (SeO2) or sodium selenite (Na2SeO3)) as a systemic deer repellent for the protection of Douglas fir seedlings is evaluated. When applied to the soil, the selenium (Se) is absorbed by the seedling roots, transported to the foliage, and thereafter volatilized. Acute phytotoxicity is observed only when Se foliar concn exceed 100 ppm, while animal repellency is demonstrated at concn as low as 1-2 ppm. ...

The substance is harmful to aquatic organisms.

Selenium dioxide is formed by combustion of elemental selenium present in fossil fuels or rubbish.

Up to 90% of the selenium content in ambient air is emitted during the burning of fossil fuels. Selenium dioxide is formed during combustion of elemental selenium present in fossil fuels.

ATMOSPHERIC FATE: Volatile selenium dioxide is expected to exist in the gaseous state in the atmosphere(1,2). Selenium dioxide released to the air from the combustion of fossil fuels is expected to be reduced to elemental selenium by sulfur dioxide formed during the combustion(2). Selenium dioxide reacting with atmospheric moisture generates selenious acid aerosols(2).

The atmospheric level of selenium in most urban regions ranges from 0.1 to 10 ng/cu m. A greater part of the atmospheric selenium is bound to fly ash and to suspended particles that contain from 1.4 to 11 ug/g and from 1 to 110 ug/g, respectively.

... by ingestion and inhalation (dust).

Selenium dioxide can affect the body if it is inhaled, if it comes in contact with the eyes or skin, or if it is swallowed. Selenium dioxide may enter the body through the skin.

ACUTE POISONING THROUGH INHALATION MAY OCCUR IN INDUSTRY (SELENIUM DUST & FUMES, SELENIUM DIOXIDE & HYDROGEN SELENIDE). ...

Selenium fumes may contain selenium dioxide in concentrations as high as 50% and are often described as the main selenium problem in the work environment.

For more Probable Routes of Human Exposure (Complete) data for SELENIUM DIOXIDE (9 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 D010; U204, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Health: TOXIC; inhalation, ingestion, or skin contact with material may cause severe injury or death. Contact with molten substance may cause severe burns to skin and eyes. Avoid any skin contact. Effects of contact or inhalation may be delayed. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution.

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Fire or Explosion: Non-combustible, substance itself does not burn but may decompose upon heating to produce corrosive and/or toxic fumes. Some are oxidizers and may ignite combustibles (wood, paper, oil, clothing, etc.). Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated.

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Public Safety: CALL Emergency Response Telephone Number ... As an 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. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate enclosed areas.

/GUIDE 154: SUBSTANCES - TOXIC AND/OR CORROSIVE (NON-COMBUSTIBLE)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible.

For more DOT Emergency Guidelines (Complete) data for SELENIUM DIOXIDE (8 total), please visit the HSDB record page.

IMO 6.1; Selenium oxide

NA 2811; Selenium oxide

UN 3283; Selenium compound, solid, n.o.s

49 233 40; Selenium oxide

Do not transport with food and feedstuffs.

Symbol: T, N; R: 23/25-33-50/53; S: (1/2)-20/21-28-45-60-61; Note: A

UN Hazard Class: 6.1; UN Pack Group: II