MB is used primarily as a soil fumigant with secondary uses for
perishable commodities and treatment of closed structures. The U.S.
Environmental Protection Agency has classified MB as a “Restricted
Use Pesticide,” i.e., a pesticide that may be purchased and used only by
certified applicators or persons under their direct supervision. Its use
is currently being phased out by the EPA following obligations under
the Montreal Protocol on Substances that Deplete the Ozone Layer [4].
Although someMB is formed naturally by algae or kelp in the ocean, exposure
to naturally formed gas does not occur. A very toxic fumigant gas
with poor olfactory warning properties, the gas has caused severe poisoning
and death during application due to inadvertent spread, cleanup
operations and premature entry into fumigated places, emphasizing
the need for continuous monitoring in and around fumigation sites as
an integral part of good fumigation practice