Styrene oxide is considered toxic, mutagenic, and possibly carcinogenic. There are no known carcinogenic and mutagenic effects. Cancer is caused by inhaling carcinogenic substances in tobacco smoke. Tar includes the majority of mutagenic and carcinogenic agents in tobacco smoke. Shale oil contains polycyclic aromatic hydrocarbons which are carcinogenic. At room temperature it is a flammable, carcinogenic, mutagenic, irritating, and anaesthetic gas. No relevance for humans concerning carcinogenic and genotoxic effects can be derived. It is highly toxic, flammable, and carcinogenic. The essential oil contains cedrol which has toxic and possibly carcinogenic properties. It is toxic and may be carcinogenic in humans. Silica-based aerogels are not known to be carcinogenic or toxic. Aflatoxins are among the most carcinogenic substances known. No evidence has been validated that zirconium is carcinogenic or genotoxic. In 2008, high levels of potentially carcinogenic flame retardant chemicals were found in Tasmanian devils. No data on human carcinogenic, teratogenic, or developmental effects have been created.