Wonder what the "several other substances" might be.
regards - red
http://www.mindfully.org/GE/Bacillus-thuringiensis-Bt.htm
In a purified form, some of the proteins produced by Bt are acutely toxic to mammals. However, in their natural form, acute toxicity of commonly-used Bt varieties is limited to caterpillars, mosquito larvae, and beetle larvae. Bt is closely related to B. cereus, a bacteria that causes food poisoning and to B. anthracis, the agent of the disease anthrax.
Few studies have been conducted on the chronic health effects, carcinogenicity, or mutagenicity of Bt. People exposed to Bt have complained of respiratory, eye, and skin irritation, and one corneal ulcer has occurred after direct contact with a Bt formulation. People also suffer from allergies to the "inert" (secret) ingredients. People with compromised immune systems may be particularly susceptible to Bt.