Sodium Dithionite

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

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

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.

· 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.

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

· 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.

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

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

General First Aid:

General First Aid:

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

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

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].

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.

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.

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.

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.

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.

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/

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.

/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.

Cough. Sore throat.

Redness. Pain.

Nausea. Abdominal pain. Vomiting. Diarrhoea.

/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.

Sodium hydrosulfite

A Commercial Grade

A Placarded Amount

Chemical or material that can be mixed with readily available materials.