Is this possibly the start of noxious chemical weapons making their way into the insurgencies tactics?

Trend started about a month ago, and while the fatalities are much lower than larger car/truck bombs, the overall panic and actual casualties is much greater. If they force U.S. troops to wear MOPP suits in the Iraqi summer, that would certainly impair their ability to function and create a greater rift between them and the Iraqi forces which are not equipped to deal with such weapons.