You can get Benzene (the petroleum naptha version) in chemical supply stores. Or you used to be able to, I don't think it has ever been a restricted chemical.
I've done a lot of searches and research, and I believe we we are at heads because we have been discussing two different things.
"Benzene" as I have been discussing it is a particular naturally occuring organic highly volitile (cumbistible) hydrocarbon with the molecule C6H6. It was discovered in the 1820s, and by the 1970s was identified as definitely carcinogenic, leading to it becoming regulated. It's use in products has since been limited or phased out.
It is not only limited, the quantity of benzene in breathing air (in workplaces) and drinking water has since become a matter of monitoring and regulating.
"Naphtha" is the name given to a family of highly combustible hydrocarbons, of which benzene is one.
Benzene can be produced (extracted) from a variety of sources, but for industrial purposes it is extracted from coal tar.
"Petroleum ether" is the name given to a crude oil extract with a weight of 0.6 and 0.8 depending on its composition, which can serve a variety of purposes, such as lamp oil or cooking gas. These substances are available under a variety of product names such as naptha and benzine.