Chemical reference number (CAS): 542-92-7

Cyclopentadiene is a manmade chemical. It is either a clear liquid or solid, with a sweet odor like turpentine or camphor. Manufacturers use cyclopentadiene to make resins and other chemicals.

Cyclopentadiene is not commonly found in home-use products. It is found in tobacco smoke and car exhaust. It’s also found in exhaust from coal and oil-fueled fires.

When released into the air, cyclopentadiene breaks down to a less toxic chemical within a few hours.

This fact sheet summarizes information about this chemical and is not a complete listing of all possible effects. It does not refer to work exposure or emergency situations.


Last Revised: May 12, 2015