Most people know that rubber cement is toxic. When used as directed, it won’t kill you but will make you sick (and your floor sticky). It’s made from a solvent called naphtha, which contains toluene and benzene. Chemicals are also known to cause central nervous system damage in large doses. Toluene has been linked to chronic fatigue syndrome, headaches, and even heart problems.  Most chemical manufacturers have pledged not to use it anymore because of its toxicity. Benzene is well known for causing leukemia. The volatile organic compounds (VOCs) in rubber cement are also extremely flammable. The vapors can build up over time and slowly enter your air ducts or crawl spaces, where they could be ignited by a pilot light or spark plug or accumulate until they explode one day.