[2] In 1943, Koppers, at the US Government's behest, built a factory in Kobuta, Pennsylvania on the Ohio River downriver from Beaver, to manufacture styrene-butadiene monomer, a building block used to make a form of synthetic rubber for the World War II defense effort.

The ethylbenzene produced there was then shipped by barge back to the Kobuta plant where it was converted to styrene monomer, and then polymerized to make expandable polystyrene.

[citation needed] In the 1960s, Koppers opened a Noise Control division and manufactured prefabricated sound traps.

[3] In 2001, the company had to close a wood treatment plant in Oroville, California due to contamination of the 205 acre facility and the surrounding area.

Although much simpler than the once sprawling chemical and aggregate conglomerate of the early-to-mid 20th century, Koppers Industries once again become successful at its core businesses.

Asphalt sealants produced from coal tar contain benzo(a)pyrene and other toxic chemicals known collectively as polycyclic aromatic hydrocarbons, or PAHs.