Tony Davis, a reporter with the Arizona Star, has written a series of articles on "Toxic Homes". The latest article discusses how toxins can "lurk in air, dust, even cleaning supplies." A previous article has scientific experts rate the different toxic risks in a home.
From the earlier article, here is Lance Wallace's list of the worst hazards in a home:
"LANCE WALLACE, Retired environmental scientist, Environmental Protection Agency.
1) Passive smoking.
2) Lead, probably through household dust.
3) Radon (a naturally occurring, radioactive underground gas that hasn't been a big problem in Tucson).
4) Particles from indoor combustion sources such as cooking, heating, fireplaces, toaster ovens, matches and candles."
Passive smoke was also at the top of the list for 4 of the other 5 scientists interviewed for the article, including David Layton, Wayne Ott, William Nazaroff, and Charles Weschler.