A swift and dramatic chemical confrontation is easy to associate but many small insults may go unnoticed until they pile in a heap. Homes concrete slabs, crawl spaces or basements can collect and build up rotten egg gas, trichlor and other solvents. The most dangerous chemicals are insecticides. Exposures to 3 groups may be inadvertent or deliberate. Third are pyrethroids, synthetic derivatives of chemicals from the chrysanthemum flower like permethrin, fenvalerate and fenpropinate.
Danger is underscored by the worst chemical incident in history.
Methyl diisocyante for manufacturing insecticides exploded at Bhopal, India in 1984 killed 3,000 people and injuring the brains, eyes and lungs of 200,000 neighbors. Other sources are manure pits, waste lagoons from paper pulping, hog raising, holds of fishing boats and geothermal sites. Chlorine from treatment plants for drinking water, sewage and swimming pools, paper and cloth bleaching and making plastics spills from tankers on rail or road, delivery and storage. Formaldehyde, glutaraldehyde and other aldehydes from fiberglass batt making, fabricating aircraft fuselage, cabin and wing parts, carbonless copy paper and for medical-dental sterilizing and fixing tissues for sectioning and microscopic diagnosis. Trichloroethylene trichlor TCE, a metal degreaser and cleaner poisons the underground rivers from dumping.