Group A- Chemicals that form explosive levels of peroxides without concentration (Safe storage time after opening - 3 months) Chemical CAS # Synonym State Ref. 000106- Butadiene(1,3) 1,3-Butadiene gas 4 99-0 000126- 2-Chloro-1,3- Chloroprene (1,3) liquid 4 99-8 butadiene 000821- Divinyl acetylene 1,5-Hexadien- 3-yne liquid 5 08-9 000108- Isopropyl ether liquid 5 20-3 000116- Tetrafluoroethylene gas 4 14-3 000109- Vinyl ether Divinyl ether liquid 5 93-3 000075- 1,1- Vinylidene chloride liquid 5 35-4 Dichloroethylene Group B-Chemicals that form explosive levels of peroxides on concentration (Safe storage time after opening - 12 months) Chemical CAS # Synonym State Ref. 000105- Acetal liquid 5 57-7 000075- Acetaldehyde liquid 4 07-0 000100- Benzyl alcohol liquid 4 51-6 000078- 2-Butanol liquid 4 92-2 000108- Cyclohexanol liquid 4 93-0 000110- Cyclohexene liquid 5 83-8 000822- 2-Cyclohexen-1-ol liquid 4 67-3 000142- Cyclopentene liquid 5 29-0 000091- Decahydronaphthalene liquid 4 17-8 000460- Diacetylene gas 5 12-8 000077- Dicyclopentadiene liquid 5 73-6 Diethylene glycol 000111- Diglyme liquid 5 dimethyl ether 96-6 000123- Dioxane 1,4-Dioxane liquid 5 91-1 Ethylene glycol 000110- Glyme liquid 5 dimethyl ether 71-4 000060- Ethyl ether Diethyl ether liquid 5 29-7 000110- Furan liquid 5 00-9 000589- 4-Heptanol liquid 4 55-9 000626- 2-Hexanol liquid 4 93-7 000098- Isopropyl benzene Cumene liquid 5 82-8 000074- Methyl acetylene Propyne gas 5 99-7 000123- 3-Methyl-1-butanol Isoamyl alcohol liquid 4 51-3 000096- Methyl cyclopentane liquid 5 37-7 000108- Methyl isobutyl ketone Methyl-i-butyl ketone liquid 5 10-1 000108- 4-Methyl-2-pentanol liquid 4 11-2 006032- 2-Pentanol liquid 4 29-7 000821- 4-Penten-1-ol liquid 4 09-0 000098- alpha-Methyl-benzyl 1-Phenylethanol liquid 4 85-1 alcohol 000060- 2-Phenylethanol Phenethyl alcohol liquid 4 12-8 000109- Tetrahydrofuran liquid 5 99-9 000119- Tetrahydronaphthalene liquid 5 64-2 Group C- Chemicals which may autopolymerize as a result of peroxide accumulation (Safe storage time after opening: inhibited chemicals- 12 months; uninhibited chemicals: - 24 hours) Chemical CAS # Synonym State Ref. 000079- Acrylic acid(2) liquid 5 10-7 000107- Acrylonitrile(2) liquid 5 13-1 000106- Butadiene(1,3) gas 5 99-0 000689- Vinyl acetylene & Buten-3-yne gas 5 97-4 Butenyne 000126- 2-Chloro-1,3- Chloroprene(1,3) liquid 5 99-8 butadiene 000079- Chlorotrifluoroethylene gas 5 38-9 000080- Methyl methracrylate(2) liquid 5 62-6 000100- Styrene liquid 5 42-5 000116- Tetrafluoroethylene gas 5 14-3 000108- Vinyl acetate liquid 5 05-4 000075- Vinyl chloride Mono-chloroethylene gas 5 01-4 000075- Vinylidene chloride 1,1-Dichloroethylene liquid 5 35-4 000100- 2-Vinyl pyridine liquid 5 69-6 000100- 4-Vinyl pyridine liquid 5 43-6 Notes 1. When stored as a liquid monomer. 2. Although these form peroxides, no explosions involving these monomers have been reported. 3. Also stored as a gas in gas cylinders. 4. Kelly, R.J., Review of Safety Guidelines for Peroxidizable Organic Chemicals, Chemical Health and Safety, September/October, 1996 5. National Research Council, Prudent Practices in the Laboratory, Handling and Disposal of Chemicals; National Academy Press; Washington, D.C., 1999 .