We like this account of the dangers posed by mercury emissions from crematoria:
Mercury is an odd element. It is a metal, yet liquid at ambient temperature and it is very volatile, easily becoming a gas. Keep in mind mercury is an element, therefore cannot be destroyed.
When mercury is emitted from the stack of an incinerator, it exists in its gaseous state while dropping to the surrounding terrain. When atmospheric mercury falls to Earth, it does so as a dry deposition. Bacteria in soils and water then convert this mercury into the very toxic and lethal methylmercury, and it is this form of mercury that is taken up by tiny aquatic plants and organisms. Fish, for instance, that eat these plants and organisms build up methylmercury in their tissue. As bigger fish eat the smaller fish, the methylmercury is concentrated farther up the food chain. This process is referred to as ” bio-accumulation.” This accumulation of methylmercury can reach a level millions of times higher than the water it came from.
Methylmercury is freely transported across the human blood brain barrier, as well as across the placenta, where it is absorbed by the developing fetus. Children with this history show a loss of IQ points, decreased performance of language skills and memory function, as well as attention deficits. In adults there can be cardiovascular diseases such as heart attacks and autoimmune effects.