absorbed through the flame. the amount of light absorbed is proportional to the concentration of the element in the solution. and what was the element found in the solution? lead. this meant that it was leaded gasoline on the camiolos' wood floors. but how did this happen? since leaded gasoline hadn't been sold in this country for over 15 years. >> many of the poorly constructed houses i have looked at were built in the early '70s. and they were built by contractors who were cutting corners. >> flooring contractors often used gasoline as a thinner so the varnish would go onto the wooden floors more easily. this was cheaper than using high-quality thinners. >> no one refuted the fact that that was a common practice, that they did use gas in finishing of the hardwood floors. so i'm convinced that's where that gas came from.