International Chemical Safety Cards SODIUM DITHIONITE ICSC: 1717 Sodium hypodisulfite Disodium hydrosulfite Sodium hydrosulfite Sodium hyposulfite Na2S2O4 Molecular mass: 174.1 ICSC #    1717 CAS #     7775-14-6 UN #        1384 EC #         016-028-00-1 April 11, 2008 Validated TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Combustible. Gives off irritating or toxic fumes (or gases) in a fire. NO open flames. NO contact with combustibles, water. Carbon dioxide. Dry sand. Special powder. Water in large amounts. EXPLOSION EXPOSURE PREVENT DISPERSION OF DUST!  •INHALATION Cough. Sore throat. Local exhaust or breathing protection. Fresh air, rest. Seek medical attention if you feel unwell .  •SKIN Protective gloves. Remove contaminated clothes. Rinse and then wash skin with water and soap.  •EYES Redness. Pain. Safety goggles . Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.  •INGESTION Nausea. Abdominal pain. Vomiting. Diarrhoea. Do not eat, drink, or smoke during work. Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Personal protection: filter respirator for particulates and acid gases adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. Carefully collect remainder, then remove to safe place. Do NOT absorb in saw-dust or other combustible absorbents. Do NOT let this chemical enter the environment. Dry. Well closed. Avoid any contact with moisture. Separated from strong oxidants, acids, Store in an area without drain or sewer access. Xn symbol R: 7-22-31 S: 2-7/8-26-28-43 UN Hazard Class: 4.2 UN Packing Group: II Signal: Warning Flame Self-heating in large quantities; may catch fire May be harmful if swallowed Causes eye irritation Harmful to aquatic life SEE IMPORTANT INFORMATION ON BACK ICSC: 1717 Prepared in the context of cooperation between the International Programme on Chemical Safety & the Commission of the European Communities (C) IPCS CEC 1994. No modifications to the International version have been made except to add the OSHA PELs, NIOSH RELs and NIOSH IDLH values.

International Chemical Safety Cards SODIUM DITHIONITE ICSC: 1717 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: WHITE CRYSTALLINE POWDER . PHYSICAL DANGERS: CHEMICAL DANGERS: The substance decomposes on heating above 100°C producing toxic fumes including sulfur oxides . The substance is a strong reducing agent and reacts with oxidants. The substance decomposes on contact with acid(s) producing toxic gases . Contact with water, moisture or moist air can cause a spontaneous ignition. OCCUPATIONAL EXPOSURE LIMITS: MAK not established. TLV not established. ROUTES OF EXPOSURE: The substance can be absorbed into the body by ingestion . INHALATION RISK: A harmful concentration of airborne particles can be reached quickly when dispersed, especially if powdered. EFFECTS OF SHORT-TERM EXPOSURE: The substance is irritating to the eyes and the respiratory tract . EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: PHYSICAL PROPERTIES Decomposes at >100°C Density: 2.4 g/cm³ Solubility in water, g/100 ml at 20°C: 25 (moderate) Flashpoint: >100 °C o.c. Octanol/water partition coefficient as log Pow: < -4.7 ENVIRONMENTAL DATA The substance is harmful to aquatic organisms. N O T E S Transport Emergency Card: TEC (R)-42GS4-II+III NFPA Code: H2; F1; R2; ADDITIONAL INFORMATION ICSC: 1717 SODIUM DITHIONITE (C) IPCS, CEC, 1994

IMPORTANT LEGAL NOTICE: Neither NIOSH, the CEC or the IPCS nor any person acting on behalf of NIOSH, the CEC or the IPCS is responsible for the use which might be made of this information. This card contains the collective views of the IPCS Peer Review Committee and may not reflect in all cases all the detailed requirements included in national legislation on the subject. The user should verify compliance of the cards with the relevant legislation in the country of use. The only modifications made to produce the U.S. version is inclusion of the OSHA PELs, NIOSH RELs and NIOSH IDLH values.