Its use in construction was outlawed in the late 70's after it was found to be highly carcinogenic when inhaled.

The experiments were done to determine the effects of mustard gas, now known to be highly carcinogenic (cancer causing).

Paraxylene is a hazardous, highly carcinogenic chemical that can be fatal if breathed in, ingested or absorbed through skin.

This prevents the formation of dioxins, highly carcinogenic pollutants.

All are highly carcinogenic; plutonium is one of the deadliest substances known.

The purpose was to protect residents from radioactive iodine, a highly carcinogenic material found in nuclear reactors which had been released by the damaged reactor.

In 1994 Condea Vista leaked about 47 million pounds of highly carcinogenic ethylene dichloride into the river, and then tried to cover up.

He said in a telephone interview that the compounds are "highly carcinogenic, equal to nitrosamines."

Thus, highly carcinogenic PAHs may be small or large.