International Chemical Safety Cards DICUMYL PEROXIDE ICSC: 1346 Peroxide, bis(1-methyl-1-phenylethyl) Bis(alpha,alpha-dimethylbenzyl)peroxide Diisopropylbenzene peroxide C18H22O2 / (C6H5C(CH3)2O)2 Molecular mass: 270.4 ICSC #    1346 CAS #     80-43-3 RTECS # SD8150000 UN #        3110 EC #         617-006-00-X October 18, 1999 Peer reviewed TYPES OF HAZARD/ EXPOSURE ACUTE HAZARDS/ SYMPTOMS PREVENTION FIRST AID/ FIRE FIGHTING FIRE Combustible. NO open flames. Powder, water spray, foam, carbon dioxide. EXPLOSION Finely dispersed particles form explosive mixtures in air. Prevent deposition of dust; closed system, dust explosion-proof electrical equipment and lighting. EXPOSURE PREVENT DISPERSION OF DUST!  •INHALATION Cough. Sore throat. Local exhaust or breathing protection. Fresh air, rest.  •SKIN Redness. Protective gloves. First rinse with plenty of water, then remove contaminated clothes and rinse again.  •EYES Redness. Safety spectacles, or eye protection in combination with breathing protection. First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.  •INGESTION Do not eat, drink, or smoke during work. Rinse mouth. Give plenty of water to drink. Refer for medical attention. SPILLAGE DISPOSAL STORAGE PACKAGING & LABELLING Remove all ignition sources. Sweep spilled substance into containers; if appropriate, moisten first to prevent dusting. Carefully collect remainder, then remove to safe place. Do NOT let this chemical enter the environment. (Extra personal protection: P2 filter respirator for harmful particles). Fireproof. Separated from combustible and reducing substances, strong oxidants, strong acids, bases , and heavy metals . Cooled. Keep in the dark. Well closed. Keep under inert gas. O symbol Xi symbol N symbol R: 7-36/38-51/53 S: 2-3/7-14-36/37/39-61 UN Hazard Class: 5.2 UN Packing Group: II SEE IMPORTANT INFORMATION ON BACK ICSC: 1346 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 DICUMYL PEROXIDE ICSC: 1346 I M P O R T A N T D A T A PHYSICAL STATE; APPEARANCE: YELLOW TO WHITE CRYSTALLINE POWDER PHYSICAL DANGERS: CHEMICAL DANGERS: The substance decomposes rapidly on heating and under influence of light , causing fire and explosion hazard. Reacts violently with acids , bases , reducing agents , and heavy metals. OCCUPATIONAL EXPOSURE LIMITS: TLV not established. ROUTES OF EXPOSURE: The substance can be absorbed into the body by inhalation of its aerosol. INHALATION RISK: Evaporation at 20°C is negligible; a harmful concentration of airborne particles can, however, be reached quickly when dispersed. EFFECTS OF SHORT-TERM EXPOSURE: The substance irritates the eyes , the skin , and the respiratory tract . EFFECTS OF LONG-TERM OR REPEATED EXPOSURE: PHYSICAL PROPERTIES Boiling point (decomposes): 130°C Melting point: 39°C Density: 1.0 g/cm3 Solubility in water, g/100 ml: none Relative vapour density (air = 1): 9.3 Flash point: 71°C c.c. Octanol/water partition coefficient as log Pow: 5.5 ENVIRONMENTAL DATA The substance is toxic to aquatic organisms. In the food chain important to humans, bioaccumulation takes place, specifically in fish. N O T E S ADDITIONAL INFORMATION ICSC: 1346 DICUMYL PEROXIDE (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.