[Dion]

Originally Posted by blankall

The vast majority of those chemicals are natural by-products of incompletely burning hydrocarbons. They will be found in burn. The heavy metals are from pesticides and will be found in only very trace amounts. The amount you would expect to breath in from difused second hand smoke is pretty neglible.

Really?

Secondhand smoke contains over 4000 chemicals including more than 40 cancer causing agents and 200 known poisons.

Secondhand smoke has been classified by the EPA as a Class A carcinogen - a substance known to cause cancer in humans.

Secondhand smoke contains twice as much tar and nicotine per unit volume as does smoke inhaled from a cigarette. It contains 3X as much cancer-causing benzpyrene, 5X as much carbon monoxide, and 50X as much ammonia. Secondhand smoke from pipes and cigars is equally as harmful, if not more so (Mayo Clinic release, Aug 97).

Over the past two decades, medical research has shown that non-smokers suffer many of the diseases of active smoking when they breathe secondhand smoke.

Secondhand smoke causes lung cancer and contributes to the development of heart disease. Never smoking women who live with a smoker have a 91% greater risk of heart disease. They also have twice the risk of dying from lung cancer.

Never-smoking spouses who are exposed to secondhand smoke have about 20% higher death rates for both lung cancer and heart disease.

Secondhand smoke increases heart rate and shortens time to exhaustion. Repeated exposure causes thickening of the walls of the carotid arteries (accelerates atherosclerosis) and damages the lining of these arteries.
When a pregnant woman is exposed to

http://www1.umn.edu/perio/tobacco/secondhandsmoke.html