Some time ago I read a post somewhere in Gardenweb from a person who contracted Legionaires Disease from handling material to be rendered into compost. For at least 20 years I have collected tree leaves neighbors have left at their curbs for recycling and after spreading each bag of leaves on top of the pile I would spray water on it and throw garden dirt over the wet leaves. At the end of the day I would be filthy literally from head to toe and up my nose. But I would be happy. Now a scientific article tells me why.

http://www.sciencedaily.com/releases/2007/04/070402102001.htm