A weapon of mass destruction (WMD for short) is defined as "a nuclear, biological or chemical instrument or tool which can kill large numbers of human beings, animals and plants." If you accept this definition, whether or not the use of the instrument was intentional or not, then New Hampshire can claim its very own.
When European explorers and settlers arrived on New Hampshire's shores, the Native Peoples of New Hampshire (Penacook, Abenaki, and Pocumtucks) numbered in the tens of thousands. By 1631 between about 500 and 1200 remained. Physical interaction between the Native People's and the colonists had caused this decimation by the introduction of a variety of diseases, with smallpox being the deadliest.
By 1763 the use of small pox to purposefully reduce the number of Native Peoples (a suggestion by Francis Parkman) was agreed to by General (Lord) Jeffery Amherst. The town of Amherst in Hillsborough County New Hampshire is named in honor of Lord Amherst.
By the time of the American Revolution, the dread of being exposed to small-pox while serving in the army was greater than the dread of the enemy. In New Hampshire offers as high as fifty dollars were advertised for substitutes.