US/Canadian secret human medical experimentation

I'm sure you've all seen the news about how the US has apologized for deliberately infecting people with syphilis and blacklisting them from treatment to "see what happens".  Part of a grisly history of secret human experimentation.

http://www.democracynow.org/2010/10/5/exposed_us_doctors_secretly_infect...

I remember my mom telling me about when she worked as a nurse, there was a rash of birth defects that were attributed to chemical spraying tests done over cities in canada.  Does anyone know a good source of info for this or similar tests carried out in canada?