Sodium Dithionite

H251: Self-heating; may catch fire [Danger Self-heating substances and mixtures]

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

P235, P264, P270, P280, P301+P317, P330, P407, P410, P413, P420, and P501 (click each P-code to see the statement)

H251 (100%): Self-heating; may catch fire [Danger Self-heating substances and mixtures]

H302 (99.7%): Harmful if swallowed [Warning Acute toxicity, oral]

H315 (23.1%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (33.4%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

P235, P264, P264+P265, P270, P280, P301+P317, P302+P352, P305+P351+P338, P321, P330, P332+P317, P337+P317, P362+P364, P407, P410, P413, P420, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 602 reports by companies from 10 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.

H402: Harmful to aquatic life [Hazardous to the aquatic environment, acute hazard]

H412: Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P273, and P501 (click each P-code to see the statement)

H303: May be harmful if swallowed [Warning Acute toxicity, oral]

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

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

P235, P264, P264+P265, P280, P301+P317, P302+P352, P305+P351+P338, P321, P332+P317, P337+P317, P362+P364, P407, P410, P413, and P420 (click each P-code to see the statement)

Fresh air, rest. Seek medical attention if you feel unwell.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Refer to the "General First Aid" section. (ERG, 2024)

General First Aid:

· Call 911 or emergency medical service.

· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.

· Move victim to fresh air if it can be done safely.

· Administer oxygen if breathing is difficult.

· If victim is not breathing:

-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.

-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).

-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.

· Remove and isolate contaminated clothing and shoes.

· For minor skin contact, avoid spreading material on unaffected skin.

· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.

· For severe burns, immediate medical attention is required.

· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.

· Keep victim calm and warm.

· Keep victim under observation.

· For further assistance, contact your local Poison Control Center.

· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.

In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF. Some of these materials may react violently with water. CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.

SMALL FIRE: Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.

LARGE FIRE: DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. If it can be done safely, move undamaged containers away from the area around the fire.

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 or in contact with substance. 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. (ERG, 2024)

Use carbon dioxide, dry sand, special powder, water in large amounts.

Special protective equipment for fire-fighters: Wear self contained breathing apparatus for fire fighting if necessary.

Use only flooding quantities of water. Monitor temperature of containers exposed to fire for at least 48 hours to verify decomposition has not begun in the sealed container.

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· Stay upwind, uphill and/or upstream.

· Keep unauthorized personnel away.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

· Do not touch or walk through spilled material.

· Stop leak if you can do it without risk.

Small Spill

CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal.

CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.

· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.

· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.

· Prevent entry into waterways, sewers, basements or confined areas.

H2S SO2 - when spill Sodium hydrosulfite into water.

Excerpt from ERG Guide 135 [Substances - Spontaneously 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: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1384 datasheet.

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)

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.

· For highlighted materials: see Table 1 - Initial Isolation and Protective Action Distances.

· For non-highlighted materials: increase the immediate precautionary measure distance, in the downwind direction, as necessary.

· 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.

When spilled in water

Small spill:

- ISOLATE in all directions: 30 m (100 ft)

Large spill:

- ISOLATE in all directions: 60 m (200 ft)

- PROTECT people from downwind during DAY time: 0.1 km (0.1 mi)

- PROTECT people from downwind during NIGHT time: 0.4 km (0.3 mi)

- PROTECT people from downwind during DAY time: 0.5 km (0.3 mi)

- PROTECT people from downwind during NIGHT time: 2.1 km (1.3 mi)

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into covered containers. Carefully collect remainder. Then store and dispose of according to local regulations. Do NOT absorb in saw-dust or other combustible absorbents.

Keep water away from release. Prompt cleanup and removal are necessary. Control runoff and isolate discharged material for proper disposal.

Personal precautions: Wear respiratory protection. Avoid dust formation. Avoid breathing dust. Ensure adequate ventilation.

Methods for cleaning up: Pick up and arrange disposal without creating dust. Keep in suitable, closed containers for disposal.

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.

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Observe all federal, state, and local environmental regulations. Contact a licensed professional waste disposal service to dispose of this material.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

If material not on fire and not involved in fire: Do not use water. Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Keep material dry. /Sodium dithionite/

Hygiene measures: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk.

SMALL SPILL: CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

Dry. Well closed. Separated from strong oxidants and acids. Store in an area without drain or sewer access.

Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Do not store near acids. Air sensitive. Heat sensitive. Moisture sensitive. Handle under inert gas. Protect from moisture.

Store in a cool, dry, well-ventilated location. Outside or detached storage is preferred. Separate from combustibles and oxiding materials. Immediately remove and properly dispose of any spilled material.

Materials to avoid: strong oxidizing agents, acids.

· Wear positive pressure self-contained breathing apparatus (SCBA).

· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.

· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

The compound is currently at the Holding Status AEGLs which have been reviewed by the NAC/AEGL Committee and are on hold due to insufficient data to develop AEGL values.

AEGLs Status: Holding

7.5 [mg/m3]

83 [mg/m3]

500 [mg/m3]

· DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF.

· Some of these materials may react violently with water.

CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.

Small Fire

· Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.

Large Fire

· DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn.

CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.

· If it can be done safely, move undamaged containers away from the area around the fire.

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 or in contact with substance.

· 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.

Holding Status AEGL that has been reviewed by the NAC/AEGL Committee and is on hold due to insufficient data to develop AEGL values: 7775-14-6 Sodium dithionite.

A harmful concentration of airborne particles can be reached quickly when dispersed, especially if powdered.

The substance is irritating to the eyes and respiratory tract.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:

Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE. Structural firefighters' protective clothing provides thermal protection but only limited chemical protection. (ERG, 2024)

Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a dust mask type N95 (US) or type P1 (EN 143) respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

Hand protection: The selected protective gloves have to satisfy the specifications of EU Directive 89/686/EEC and the standard EN 374 derived from it. Handle with gloves.

Eye protection: Safety glasses with side-shields conforming to EN166.

Skin and body protection: Choose body protection according to the amount and concentration of the dangerous substance at the work place.

Wear full protective clothing and positive pressure self-contained breathing apparatus.

NO open flames. NO contact with combustible substances or water.

PREVENT DISPERSION OF DUST!

Use local exhaust or breathing protection.

Protective gloves.

Wear safety goggles.

Do not eat, drink, or smoke during work.

Sodium dithionite is a whitish to light yellow crystalline solid having a sulfur dioxide-like odor. It spontaneously heats on contact with air and moisture. This heat may be sufficient to ignite surrounding combustible materials. Under prolonged exposure to fire or intense heat containers of this material may violently rupture. It is used in dyeing and to bleach paper pulp.

Liquid; Other Solid; Dry Powder

White to grayish-white granular powder with a sulfur dioxide odor; [CHEMINFO MSDS]

WHITE CRYSTALLINE POWDER.

White or grayish-white crystalline powder

Light-lemon-colored solid in powder or flake form

White, colorless or yellow-white crystals

Faint sulfurous

Slight characteristic odor

52 °C (decomposes)

about 100 °C (open cup)

>100 °C o.c.

Slightly sol in alcohol; very soluble in water

Slightly sol in cold water; insoluble in acids

At 20 °C, 24.1 g/100 g water

Solubility in water, g/100ml at 20 °C: 25 (moderate)

2.38 g/cu cm

Na2S2O4.2H2O, mol wt 210.146 ... crystallizes in thin, yellowish shiny, soft prisms of density 1.58 g/cu cm /Dihydrate/

2.4 g/m³

log Kow = < -4.7

Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed. Keep away from combustible material.

Oxidizes in air, (more readily so in presence of moisture or when in solution) to bisulfite and bisulfate and acquires an acid reaction.

Sodium dithionite is not stable under physiological conditions, with the rate of decomposition increasing with increasing acidity. Upon contact with moisture, it is oxidized to hydrogen sulfite, sulfite and hydrogen sulfate, and under strongly acidic conditions it may liberate sulfur dioxide.

about 190 °C

A batch decomposed violently during drying in graining bowl. No explanation was offered but contamination with water and/or oxidant seems likely. Thermal decomposition occurs violently at 190 °C.

Strong reducing agent; also available in liquid form

Decomposes violently when heated to 190 °C and emits toxic fumes of SOx and Na2O.

Metals -> Hydrosulfites

Reactive agents - 2nd degree

Viscosity controlling; Reducing

Use unspecified -> FDA Substance added to food

FCS -> FDA Inventory of Food Contact Substances Listed in 21 CFR

Sodium dithionite is a combustible solid which slowly decomposes when in contact with water or water vapor, forming thiosulfates and bisulfites. This reaction evolves heat, which can further accelerate the reaction or cause surrounding materials to burn. If the mixture is confined, the decomposition reaction can result in pressurization of the container which may then rupture forcefully. Upon standing in air it slowly oxidizes, generating toxic sulfur dioxide gas. (NFPA, 2010)

Anhydrides

Strong Reducing Agent

Water-Reactive

Pyrophoric

Use of scoop contaminated with sodium dithionite for sodium chlorite caused ignition of latter. Material containing sulfur (dithionite, natural rubber gloves) cause decomp of sodium chlorite and contact should be avoided.

Reacts on exposure to moist air to form toxic and corrosive fumes with generation of heat and risk of combustion. The substance is a strong reducing agent and reacts violently with oxidants. Upon contact with dry air the substance passes into a mixt of sodium bisulfate and sodium bisulfite. Reacts with acids to form sulfur oxides. /Dihydrate/

Reacts with oxidizing agents, acidic materials, moisture. Exposure to moisture either from humid air or from small amounts of water can result in spontaneous chemical reactions which may generate sufficient heat to initiate thermal decomposition. Heat above 50 °C can also initiate thermal decomposition.

Human Health: Sodium dithionite is not stable under physiological conditions, with the rate of decomposition increasing with increasing acidity. Upon contact with moisture, it is oxidized to hydrogen sulfite, sulfite and hydrogen sulfate, and under strongly acidic conditions it may liberate sulfur dioxide. Under anaerobic conditions (such as in the lower gastrointestinal tract), hydrogen sulfite and thiosulfate may be formed. Hydrogen sulfite can be absorbed after ingestion. It is efficiently metabolized, and the major part rapidly excreted as sulfate into the urine. The acute oral LD50 of sodium dithionite in rats was about 2500 mg/kg bw, with atony, gastro-intestinal irritation, diarrhea and dyspnea as the main clinical and pathological signs at doses near to or exceeding the LD50. There were no acute dermal and no valid acute inhalation studies available. Sodium dithionite was slightly irritating to the skin, and strongly irritating to the eyes of rabbits. Under acidic conditions, sodium dithionite may liberate sulfur dioxide, which is known to induce respiratory irritation in humans. There was no animal data available regarding sensitization. In humans, allergic dermatitis from exposure to sulfites is rare and, consequently, sodium dithionite is not considered to possess a significant skin sensitization potential. Although there were no specific reports with regard to sodium dithionite available, the potential for allergoid reactions ("sulfite-asthma") should be assumed in sensitive individuals following oral or inhalation exposure. Sodium dithionite was not tested for its toxicity after repeated dosing. Due to its rapid degradation under in vivo conditions, the toxicity data on its decomposition products were used for the evaluation of this endpoint. The conversion products, including sulfite, hydrogen sulfite, sulfate and thiosulfate, are considered as substances of very low order systemic toxicity. It should be noted that sulfites, in general, reduce the thiamine content in food. For disodium disulfite, oral NOAELs (30 and 104 weeks) of 942 mg/kg bw/day and 217 mg/kg bw/day were obtained for systemic toxicity and local gastrointestinal toxicity in rats, respectively. These results appear to be sufficiently representative also for the assessment of sodium dithionite. Repeated dose studies in animals using the dermal or respiratory routes were not available. Sodium dithionite was not mutagenic in standard bacterial tests with and without metabolic activation (OECD TG 471, 472). No experimental data was available on the potential of sodium dithionite to induce chromosomal aberrations in vitro. An increase in the frequency of micronuclei in bone marrow cells of mice was found after intraperitoneal injection of high doses (2 x 500 or 2 x 750 mg/kg bw) of a mixture of sodium hydrogen sulfite and sodium sulfite, the degradation products of sodium dithionite under physiological conditions. No experimental data were available on the carcinogenic potential of sodium dithionite. In 1992, IARC concluded that degradation products of dithionite, i.e. sulfur dioxide, sulfites, hydrogen sulfites and metabisulfites "are not classifiable as to their carcinogenicity to humans (Group 3)". Sodium dithionite has not been tested for its effects on reproduction and development. Based on its physicochemical behavior and its rapid conversion in the body, it is not expected that the intact molecule reaches the reproductive organs, or has any direct effect on reproduction and development. Data relating to the degradation products of sodium dithionite do also not indicate any adverse effects. At high dietary doses, which can cause maternal malnutrition and destruction of thiamine, fetal growth retardation was however observed. In a rat dietary study with sodium sulfite (similar to OECD TG 414), the NOAEL for developmental toxicity was at 5 % (about 1450 mg/kg bw/day; highest tested dose). At this dose clear signs of maternal toxicity were observed (LOAEL, maternal toxicity: 5 % in diet = about 1450 mg/kg bw/day). The NOAEL for maternal toxicity was at 2.5 % in feed (about 850 mg/kg bw/day). Environment: From acute toxicity test to fish (Leuciscus idus), 96-hr LC50 was 62.3 mg/L. For algae (Scenedesmus subspicatus), 72-hr ErC50 was 206 mg/L and 72-hr NOErC was 62.5 mg/L (corresponding values for biomass are 135 and 62.5 mg/L respectively; nominal concentration). For Daphnia magna, the acute toxicity value of 48-hr EC50 was 98.3 mg/L, and the chronic value of 21-day NOEC was > 10 mg/L. Due to oxygen concentrations < 1 mg/L at test start in high test concentrations in the fish and acute daphnia test, it cannot be excluded that the effect values found in these studies are at least partly caused by oxygen deficiency. A PNEC of 0.1 mg/L for the aquatic organisms was calculated from the chronic value (NOEC for daphnia > 10 mg/L) using an assessment factor of 100.

The substance can be absorbed into the body by ingestion.

Cough. Sore throat.

Redness. Pain.

Nausea. Abdominal pain. Vomiting. Diarrhoea.

Other Poison - Chemical Asphyxiant

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

LD50 Rat oral approx 2500 mg/kg bw

LD50 Mouse ip 900 mg/kg bw

Sodium hyposulfite at a concentration of 1 x 10-5 M decreased the number of chromosome fragments produced by cobalt 60 gamma rays in Tradescantia paludosa (clone B2-2) root tip by 46%. Concentrations of 1 x 10-4 or 1 x 10-3 M were no more effective, and the 1 x 10-3 M concentration was toxic to the root tips.

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. /Sulfur 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 pulmonary edema 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 ... . Administer activated charcoal ... . Cover skin burns with dry sterile dressings after decontamination ... . /Sulfur 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 bronchospasms ... . 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 ... . /Sulfur and related compounds/

/SIGNS AND SYMPTOMS/ Probable oral lethal dose (human) 0.5-5 g/kg bw. Because of rapid oxidation to sulfates, sulfites are well tolerated until large dises are reached; then violent colic and diarrhea, circulatory disturbances, central nervous depression, and death are described.

/SIGNS AND SYMPTOMS/ May cause respiratory tract irritation ... May cause skin irritation. May cause eye irritation.

/CASE REPORTS/ ... A female dry cleaner is reported to have developed hand dermatitis presumably due to regular preparation of sodium sulfite solutions. Patch testing gave a positive response on application of a 0.5% and 1% solution of sodium dithionite.

/ALTERNATIVE and IN VITRO TESTS/ Incubation of normal human erythrocytes with sodium dithionite resulted in the formation of Heinz bodies. Addition of superoxide dismutase to the incubation medium incr the formation of Heinz bodies by sodium dithionite.

/OTHER TOXICITY INFORMATION/ Under acidic conditions, sodium dithionite may liberate sulfur dioxide (SO2). Sulfur dioxide is known to induce respiratory irritation and in disposed humans also bronchospasms. The hypersensitivity reaction is also known as "sulfite-asthma" and linked to SO2 exposure or the use of SO2 or bisulfite as antioxidants in foodstuffs. About 10 % of asthmatic humans are reportedly sulfite- or SO2-sensitive.

/LABORATORY ANIMALS: Acute Exposure/ 2% aq soln of sodium hydrosulfite adjusted to pH 7 with sodium bicarbonate tested on rabbit eyes by irrigation of surface of eye for 10 min after removal of corneal epithelium caused slight corneal edema ...

/LABORATORY ANIMALS: Acute Exposure/ For sodium dithionite (tested as suspension in aqueous carboxymethylcellulose), an oral LD50 of about 2500 mg/kg bw was determined for rats. No clinical signs were noted at doses up to and including 1600 mg/kg bw. At higher doses (>= 2000 mg/kg bw), clinical signs included atony, dyspnea and diarrhea. Gross pathology revealed acute hyperemic congestion, cardiac dilatation, gastrointestinal irritation and dilatation, associated with bloody ulceration in animals administered doses of 2500 mg/kg bw or higher.

/LABORATORY ANIMALS: Acute Exposure/ An 80% aqueous suspension of sodium dithionite tested in two rabbits under occlusive conditions for 20 hours produced mild skin erythema. The mild erythema seen at 24 hours post-treatment did not persist to 8 days. With an exposure time of 20 hours (instead of 4 hours), and occlusive conditions (instead of semi-occlusive), the test conditions were more stringent than those required in the current OECD TG 404.

/LABORATORY ANIMALS: Acute Exposure/ Sodium dithionite was tested for its effects on the eye of rabbits in a study performed in accordance with OECD TG 405. 97 mg of the finely powdered test substance (purity 88%) were instilled in the conjunctival sac of three rabbits, and washed out with physiological saline after one hour of exposure. In all animals, moderate to severe erythema and slight edema were found after 1 hour and persisted until 72 and 48 hours, respectively. Mean scores for erythema were 3.0 (24 hr), 3.0 (48 hr), and 2.3 (72 hr), and for edema 1.3 (24 hr), 0.67 (48 hr), and 0.33 (72 hr). No changes were noted in the cornea and iris. All effects were completely reversible by day 7 after exposure except for 1 animal which still showed slight conjunctival redness.

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

LC50 Species; Leuciscus idus (ide, freshwater fish); Conditions: German Industrial Standard DIN 38 412, Part 15; Concentration: 63.2 mg/L (nominal) for 96 hr

EC50; Species: Daphnia magna (water flea); Conditions: Directive 79.831 EEC, C2; Concentration: 98.3 mg/L for 48 hr, endpoint: immobilization /Effect not given in source/

/AQUATIC SPECIES/ A test following Directive 79/831/EEC, C2, with Daphnia magna with 10 nominal concentrations, plus a control ranging from 0.976 - 500 mg/L, resulted in an EC50 (48 hr, immobilization) of 98.3 mg/L. As oxygen values in the 250 mg/L and 500 mg/L test solutions were below 1 mg/L at the beginning of the test, it cannot be excluded that the toxicity was in part due to oxygen deficiency effects.

/AQUATIC SPECIES/ In a study with Leuciscus idus, following the German Industrial Standard DIN 38 412, Part 15, six concentrations from 21.5 - 147 mg/L (nominal), plus a control and pH adjusted 147 mg/L and 500 mg/L group, were tested. An LC50 (96 hr) of 63.2 mg/L (nominal) was calculated. All fish in the pH adjusted 147 mg/L and 500 mg/L concentration groups died within one hour. Less than 1 mg/L oxygen was measured in those test solutions at test start. In a pre-test in which the fish were placed into the aquaria 1 hr after preparation of the test solution the initial oxygen consumption was compensated by the continuous aeration and the concentration of 100 mg/L did not cause any mortality or symptoms. Therefore, the toxic effect may be, in part, due to oxygen deficiency.

/AQUATIC SPECIES/ Acute toxicity to Scenedesmus subspicatus was determined in a study, following the German Industrial Standard DIN 38 412 Part 9, with 7 nominal concentrations ranging from 7.81 -500 mg/L, plus a control. The ErC50 (72 hr) for growth rate was 206 mg/L (nominal concentration) and the NOEC 62.5 mg/L (nominal concentration); corresponding values for the endpoint biomass were 135 mg/L and 62.5 mg/L respectively.

/AQUATIC SPECIES/ The following chronic toxicity test with aquatic organisms is available: Water flea (Daphnia magna): NOEC (21 d) > 10 mg/L. Three concentrations (1, 5, and 10 mg/L) were tested.

The substance is harmful to aquatic organisms.

AEROBIC: At 20 °C, the 5-day BOD of sodium dithionite was 22%, through the action of sewage bacteria(1).

The hydrolysis products of aqueous sodium dithionite solutions can be trapped as sodium 1-hydroxyalkane-sulfinates and 1-hydroxyalkanesulfonates by addition of aldehydes or ketones(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 76,179 workers (26,281 of these were female) were potentially exposed to sodium dithionite in the US(1).

LC50 Species; Leuciscus idus (ide, freshwater fish); Conditions: German Industrial Standard DIN 38 412, Part 15; Concentration: 63.2 mg/L (nominal) for 96 hr

EC50; Species: Daphnia magna (water flea); Conditions: Directive 79.831 EEC, C2; Concentration: 98.3 mg/L for 48 hr, endpoint: immobilization /Effect not given in source/

/AQUATIC SPECIES/ A test following Directive 79/831/EEC, C2, with Daphnia magna with 10 nominal concentrations, plus a control ranging from 0.976 - 500 mg/L, resulted in an EC50 (48 hr, immobilization) of 98.3 mg/L. As oxygen values in the 250 mg/L and 500 mg/L test solutions were below 1 mg/L at the beginning of the test, it cannot be excluded that the toxicity was in part due to oxygen deficiency effects.

/AQUATIC SPECIES/ In a study with Leuciscus idus, following the German Industrial Standard DIN 38 412, Part 15, six concentrations from 21.5 - 147 mg/L (nominal), plus a control and pH adjusted 147 mg/L and 500 mg/L group, were tested. An LC50 (96 hr) of 63.2 mg/L (nominal) was calculated. All fish in the pH adjusted 147 mg/L and 500 mg/L concentration groups died within one hour. Less than 1 mg/L oxygen was measured in those test solutions at test start. In a pre-test in which the fish were placed into the aquaria 1 hr after preparation of the test solution the initial oxygen consumption was compensated by the continuous aeration and the concentration of 100 mg/L did not cause any mortality or symptoms. Therefore, the toxic effect may be, in part, due to oxygen deficiency.

/AQUATIC SPECIES/ Acute toxicity to Scenedesmus subspicatus was determined in a study, following the German Industrial Standard DIN 38 412 Part 9, with 7 nominal concentrations ranging from 7.81 -500 mg/L, plus a control. The ErC50 (72 hr) for growth rate was 206 mg/L (nominal concentration) and the NOEC 62.5 mg/L (nominal concentration); corresponding values for the endpoint biomass were 135 mg/L and 62.5 mg/L respectively.

/AQUATIC SPECIES/ The following chronic toxicity test with aquatic organisms is available: Water flea (Daphnia magna): NOEC (21 d) > 10 mg/L. Three concentrations (1, 5, and 10 mg/L) were tested.

The substance is harmful to aquatic organisms.

AEROBIC: At 20 °C, the 5-day BOD of sodium dithionite was 22%, through the action of sewage bacteria(1).

The hydrolysis products of aqueous sodium dithionite solutions can be trapped as sodium 1-hydroxyalkane-sulfinates and 1-hydroxyalkanesulfonates by addition of aldehydes or ketones(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 76,179 workers (26,281 of these were female) were potentially exposed to sodium dithionite in the US(1).

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Observe all federal, state, and local environmental regulations. Contact a licensed professional waste disposal service to dispose of this material.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

If ... THERE IS NO FIRE, go directly to the Table of Initial Isolation and Protective Action Distances /(see table below)/ ... to obtain initial isolation and protective action distances. IF THERE IS A FIRE, or IF A FIRE IS INVOLVED, go directly to the appropriate guide /(see guide(s) below)/ and use the evacuation information shown under PUBLIC SAFETY. /Sodium hydrosulfite (when spilled in water)/

Table: Table of Initial Isolation and Protective Action Distances for Sodium hydrosulfite (when spilled in water) [Table#2079]

Table of Water-Reactive Materials Which Produce Toxic Gases

Table: Materials Which Produce Large Amounts of Toxic-by-Inhalation (TIH) Gas(es) When Spilled in Water [Table#2080]

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Fire or Explosion: Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated.

/GUIDE 135: SUBSTANCES - SPONTANEOUSLY COMBUSTIBLE/ Health: Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control may cause pollution.

For more DOT Emergency Guidelines (Complete) data for Sodium hydrosulfite (10 total), please visit the HSDB record page.

UN 1384; Sodium dithionite

IMO 4.2; Sodium dithionite or Sodium hydrosulfite

Usual shipping containers: glass bottle inside wooden box. Specially constructed drums.

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials.

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article.

Spontaneously Combustible

Symbol: Xn; R: 7-22-31; S: (2)-7/8-26-28-43

UN Hazard Class: 4.2; UN Pack Group: II