8
Fumigants
8.1 Introduction
Millions of pounds of fumigants are applied each year to control pests at all
stages of food production. Fumigants are important for production of strawberries, other specialty fruits, and grains. Applied preplant and subsequently
vented, they control a wide array of soil-borne pests including nematodes,
insects, and weeds. There is a growing need for fumigants use in stored
products before they are transported and processed into a number of food
products. Spices, grains, and nuts routinely receive fumigant applications.
Fumigants are volatile low-molecular-weight chemicals that can diffuse into
and out commodities or soil (Figure 8.1). Once their job of controlling pests
is complete, they can be vented. Generally, the threated commodity can then
be handle safely and eventually consumed free of pests (and pesticide residues). And fumigated felds, once vented, can grow a new crop of seedlings.
California leads the United States in producing these commodities, both for
the rest of the United States and for the export market. Hence, it is the largest
user of fumigants (Table 8.1).
On the negative side, fumigants are generally hard to confne and become
unwanted air contaminants after they do their job of killing pathogens and
microorganisms that cause spoilage. Fumigants are also toxic to people,
animals, and nontarget species, so there are many restrictions on use and
undue exposures (Table 8.2). Among the fumigants listed, chloropicrin is the
most toxic (Lee et al., 2002). Methyl bromide (MeBr) is of low acute toxicity
but is capable of producing mutagenic or carcinogenic effects upon repeated
exposures in mammals including humans. Therefore, to protect nontarget
organisms, special precautions are needed when fumigants are used (Randy
Segawa, personal communication, CDPR, April 19, 2018).
Fumigants are mobile compounds in the environment and warrant exceptional safeguards in terms of application technology, minimizing worker
exposure, and preventing movement to air and groundwater. They pose
risks to applicators and feld workers, and to a lesser extent, to those who live
in the vicinity of fumigant operations. In the past, regulatory agencies have
banned agricultural chemicals that are too mobile and toxic to guarantee
DOI: 10.1201/9781003217602-8
123
Fumigants
8.1 Introduction
Millions of pounds of fumigants are applied each year to control pests at all
stages of food production. Fumigants are important for production of strawberries, other specialty fruits, and grains. Applied preplant and subsequently
vented, they control a wide array of soil-borne pests including nematodes,
insects, and weeds. There is a growing need for fumigants use in stored
products before they are transported and processed into a number of food
products. Spices, grains, and nuts routinely receive fumigant applications.
Fumigants are volatile low-molecular-weight chemicals that can diffuse into
and out commodities or soil (Figure 8.1). Once their job of controlling pests
is complete, they can be vented. Generally, the threated commodity can then
be handle safely and eventually consumed free of pests (and pesticide residues). And fumigated felds, once vented, can grow a new crop of seedlings.
California leads the United States in producing these commodities, both for
the rest of the United States and for the export market. Hence, it is the largest
user of fumigants (Table 8.1).
On the negative side, fumigants are generally hard to confne and become
unwanted air contaminants after they do their job of killing pathogens and
microorganisms that cause spoilage. Fumigants are also toxic to people,
animals, and nontarget species, so there are many restrictions on use and
undue exposures (Table 8.2). Among the fumigants listed, chloropicrin is the
most toxic (Lee et al., 2002). Methyl bromide (MeBr) is of low acute toxicity
but is capable of producing mutagenic or carcinogenic effects upon repeated
exposures in mammals including humans. Therefore, to protect nontarget
organisms, special precautions are needed when fumigants are used (Randy
Segawa, personal communication, CDPR, April 19, 2018).
Fumigants are mobile compounds in the environment and warrant exceptional safeguards in terms of application technology, minimizing worker
exposure, and preventing movement to air and groundwater. They pose
risks to applicators and feld workers, and to a lesser extent, to those who live
in the vicinity of fumigant operations. In the past, regulatory agencies have
banned agricultural chemicals that are too mobile and toxic to guarantee
DOI: 10.1201/9781003217602-8
123