They banned more than 250 chemical pesticide products in Ontario. Researchers have found that pesticides can be associated with serious illnesses, including cancer, damage to the immune system, and neurological problems. Children are particularly vulnerable. Funny how they just found this now and these products were being sold for decades. Now, many of the weed killers are not available anymore unless you buy them in the U.S. What do you use to kill weeds and which other provinces have this ban? We remove the weeds manually by hand. One of the best ways to do it if there are not many of them.