ZINC DITHIONITE

Zinc dithionite is a white powder. It is noncombustible. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. It is used to bleach wood pulp, textiles, and other naturally occurring materials.

• Strong Reducing Agent
• Water-Reactive

Mixing with limited quantities of water can cause heating and decomposition with release of irritating gaseous sulfur dioxide. This hazard is reduced by dilution with large quantities of water.

Based on a scenario where the chemical is spilled into an excess of water (at least 5 fold excess of water), half of the maximum theoretical yield of Sulfur Dioxide gas will be created in 6.9 minutes. Experimental details are in the following: "Development of the Table of Initial Isolation and Protective Distances for the 2008 Emergency Response Guidebook", ANL/DIS-09-2, D.F. Brown, H.M. Hartmann, W.A. Freeman, and W.D. Haney, Argonne National Laboratory, Argonne, Illinois, June 2009.

Special Hazards of Combustion Products: Decomposes giving off irritating SO2. (USCG, 1999)

INHALATION: Irritation of nose and throat. EYES: Mild irritant. SKIN: Irritant. INGESTION: Nausea and vomiting. (USCG, 1999)

Undergoes a self-accelerating hydrolysis reaction upon contact with water, producing thiosulfate and bisulfite compounds and heat in neutral or acidic aqueous solution. Reacts with oxidizing agents to generate heat and products that may be flammable, combustible, or otherwise reactive. These reactions may be violent.

• Anhydrides

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below.

• Cellulose-Based Absorbents
• Mineral-Based & Clay-Based Absorbents
• Dirt/Earth

Excerpt from 171 [Substances (Low to Moderate Hazard)]:

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 1931 datasheet.

FIRE: If tank, rail car or tank truck 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, 2020)

Excerpt from 171 [Substances (Low to Moderate Hazard)]:

SMALL FIRE: Dry chemical, CO2, water spray or regular foam.

LARGE FIRE: Water spray, fog or regular foam. Do not scatter spilled material with high-pressure water streams. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal.

FIRE INVOLVING TANKS: 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 engulfed in fire. (ERG, 2020)

Excerpt from 171 [Substances (Low to Moderate Hazard)]:

Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent dust cloud. For Asbestos, avoid inhalation of dust. Cover spill with plastic sheet or tarp to minimize spreading. Do not clean up or dispose of, except under supervision of a specialist.

SMALL DRY SPILL: With clean shovel, place material into clean, dry container and cover loosely; move containers from spill area.

SMALL SPILL: Pick up with sand or other non-combustible absorbent material and place into containers for later disposal.

LARGE SPILL: Dike far ahead of liquid spill for later disposal. Cover powder spill with plastic sheet or tarp to minimize spreading. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2020)

Dust mask, chemical workers goggles, and rubber gloves. (USCG, 1999)

No information available.

Call a physician.

INHALATION: Move to fresh air.

EYES: Wash with plain water or 2% solution of sodium bicarbonate.

SKIN: Wash with soap and water.

INGESTION: Dilute chemical and empty stomach with an emetic. (USCG, 1999)

• ZINC DITHIONITE
• ZINC DITHIONITE (ZNS2O4)
• ZINC HYDROSULFITE
• ZINC HYDROSULPHITE