...Test Method for Peroxides in Styrene Monomer Active Standard ASTM D2340...the quantity of peroxides in styrene monomer both for quality control and...determination of the peroxide content of styrene monomer. 1.2 This test method...
http://www.astm.org/Standards/D2340.htm
Member Companies. CEFIC is grateful for the valuable contributions and peer review of this document by the following member companies: BASF; Bayer Material Science
http://styrenemonomer.org/
Commercially styrene is also co-produced with propylene oxide in a process known as POSM (Lyondell Chemical Company) or SM/PO for styrene monomer / propylene oxide.
http://en.wikipedia.org/wiki/Styrene