First hand smoke VS. second hand smoke?

A review, published by the Journal of the American Medical Association, in 1992, found a link between the exposure to second hand tobacco smoke, and increased risk of Heart disease death among persons who have never smoked. Furthermore, the review attributed 35,000 to 40,000 deaths per year in the United States to passive smoking. The experiments that Philip Morris tobacco company performed, in 1980s, to shed more light on the side effects of passive smoking proved that inhaled secondhand smoke is four times more toxic than firsthand smoke, a startling finding that tobacco companies deliberately hid from the people in order to protect their industry.