An Introduction to Chemical Hazards in the Workplace
” … What makes a chemical toxic?
“The toxicity of a substance is its ability to cause harmful effects. These
effects can strike a single cell, a group of cells, an organ system, or the
entire body. A toxic effect may be visible damage, or a decrease in
performance or function measureable only by a test. All chemicals
can cause harm. When only a very large amount of the chemical can
cause damage, the chemical is considered to be relatively non-toxic.
When a small amount can be harmful, the chemical …

UC Berkeley Biologist who found Atrazine linked to deformed sexual organs of frogs

Atrazine-Induced Hermaphroditism at 0.1 PPB in American Frogs (Rana pipiens): Laboratory and Field Evidence Environmental Health Perspectives; Volume 111, Number 4;April 2003
http://ehp.niehs.nih.gov/members/2003/5932/5932.html
Hermaphrodite Frogs Caused By Popular Weed Killer?
By Bijal P. Trivedi; National Geographic Today
“April 16, 2002 Atrazine, a top selling weed killer in the United States and the world, has
been found to dramatically affect the sexual development of male frogs, turning them
into hermaphroditesãcreatures with both male and female organsãat concentrations
30 times lower than those deemed safe …