Benzene is an organic hydrocarbon that is a natural component of petroleum, it is a colorless, highly flammable liquid with a sweet smell, it is partly responsible for the aroma of gasoline. Benzene is mainly used as a solvent and a precursor chemical to other materials like ethylbenzene, cumene, cyclohexane, and nitrobenzene, which are used in the manufacture of plastics, rubbers, lubricants and dyes. Benzene is highly toxic, breathing benzene fumes can be fatal due to causing vascular congestion in the brain (which is what caused Weaver's seizure); when ingested it causes irritation of the gastrointestinal tract, nausea, vomiting, stomach pain, diarrhea, dizziness, sleepiness, seizures, rapid heart rate, and death. Benzene is also a carcinogen and chronic exposure can cause aplastic anemia, acute leukemia, bone marrow abnormalities and cardiovascular disease.