Is vinyl siding dangerous to health?

Potentially...

When heated, PVC can leach small quantities of formaldehyde, sometimes lead. These fumes usually don't get inside, but if they do can cause plenty of problems, as in the case of the FEMA trailers for Katrina evacuees. Vinyl siding can be very dangerous in a fire, however, releasing hydrochloric acid fumes! Please look at this article:

http://home.howstuffworks.com/home-improvement/repair/vinyl-siding-lethal.htm