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Fumigation is a method of pest control or the removal of harmful microorganisms by completely filling an area with gaseous pesticides, or fumigants, to suffocate or poison the pests within. It is used to control pests in buildings (structural fumigation), soil, grain, and produce. Fumigation is also used during the processing of goods for import or export to prevent the transfer of exotic organisms.
Structural fumigation targets pests inside buildings (usually residences), including pests that inhabit the physical structure itself, such as woodborers and drywood termites. Commodity fumigation, on the other hand, is also to be conducted inside a physical structure, such as a storage unit, but it aims to eliminate pests from infesting physical goods, usually food products, by killing pests within the container which will house them.
Each fumigation lasts for a certain duration. This is because after spraying the pesticides, or fumigants, only the pests around are eradicated. [1]
Fumigation generally involves the following phases: first, humans are evacuated from the area intended for fumigation and the area covered to create a sealed environment. Next, the fumigant is released into the space to be fumigated. The space is held for a set period while the fumigant gas percolates through the space and acts on/kills any infestation in the area. Finally, the space is ventilated so that the poisonous gases are allowed to escape from the space, rendering it safe for humans to enter. If successful, the fumigated area is now safe and pest free. [2]
Structural fumigation techniques differ from building to building. In a residential setting, a "rubber" tent or tents, typically made of plastic/pvc coated canvas material, may be placed over the entire structure while the pesticides are being released into the vacant structure. This process is called tent fumigation, or "tenting". The sealed tent contains the poisonous gases and prevents them from escaping into the environment. This process is commonly used for the treatment of drywood termites and/or bedbugs, using sulfuryl fluoride as the pesticide (sulfuryl fluoride is a naturally occurring gas, used in much higher concentration than found in the natural atmosphere, and which leaves no physical residue). The fumigated structure can be re-occupied after the tent has been removed and the pesticide has dissipated to a safe level, with no need for physical cleaning. [3]
Fumigation of hospital rooms with high concentrations of toxic chemicals has been proposed to reduce microbial agents on hospital surfaces and to control surgical site infections. [4] Formaldehyde fumigation has long been an accepted method for areas where microbiological cleanliness is required. Fumigation with formaldehyde vapor is the recognized and most commonly used method because it is a cost-effective procedure. [ citation needed ] However, alternative methods are sought due to safety and efficacy concerns. Vaporized hydrogen peroxide is a dry gaseous method that has been used as a reliable alternative for aseptic processing isolators, and more recently, for room/facility decontamination. [5] Hydrogen peroxide and silver in solution and diluted in water is a non-toxic and low cost agent. For example, to fumigate a 1000 ft3 (~28.32 m3) area, a 20% solution (200 mL of solution in 1000 mL demineralized water) would be sprayed via fogger for 30 minutes. Fogging may be done at a rate of up to 130 mL/minute and the contact time should be at least one hour. [6]
At the heart of this technology is the use of chemicals. Ideally, these chemicals kill or passivate the targeted creatures without harming others. Usually such a feat is impossible, so fumigation is conducted in the absence of humans. [3]
chemical | boiling point/volatility | safety | comment |
---|---|---|---|
Methyl bromide | gas (4.3 °C) | , TLV-TWA 5 ppm, MAK 5 ppm. | restricted by the Montreal Protocol. |
ethylene oxide | gas (10.7 °C) | TLV-TWA 1 ppm | food |
sulfuryl fluoride | gas (-55 °C) | TLV-TWA 5 ppm, | applied in tent for termites |
chloropicrin | 112 °C | TLV-TWA 0.1 ppm, MAK 0.1 ppm, | lachrymator. |
naphthalene | sublimable solid | TLV-TWA 10 ppm, | fabrics ("mothballs") |
phosphine | gas (-87.7 °C) | ?? | rodents and insects in grain silos |
1,3-dichloropropene | 111 °C | MAK 75 ppm | soil fumigant |
Many chemicals have been discontinued owing to safety issues.
Fumigation is a hazardous operation. Generally it is a legal requirement that the operator who carries out the fumigation operation holds official certification to perform the fumigation, as the chemicals used are toxic to most forms of life, including humans. [1]
Post operation ventilation of the area is a critical safety aspect of fumigation. It is important to distinguish between the pack or source of the fumigant gas and the environment which has been fumigated. While the fumigant pack may be safe and spent, the space will still hold the fumigant gas until it has been ventilated.
Hydrogen peroxide is a chemical compound with the formula H2O2. In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution in water for consumer use and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used as both a monopropellant and an oxidizer in rocketry.
Hydrogen cyanide is a chemical compound with the formula HCN and structural formula H−C≡N. It is a highly toxic and flammable liquid that boils slightly above room temperature, at 25.6 °C (78.1 °F). HCN is produced on an industrial scale and is a highly valued precursor to many chemical compounds ranging from polymers to pharmaceuticals. Large-scale applications are for the production of potassium cyanide and adiponitrile, used in mining and plastics, respectively. It is more toxic than solid cyanide compounds due to its volatile nature. A solution of hydrogen cyanide in water, represented as HCN, is called hydrocyanic acid. The salts of the cyanide anion are known as cyanides.
Formaldehyde ( for-MAL-di-hide, fər-) (systematic name methanal) is an organic compound with the chemical formula CH2O and structure H−CHO, more precisely H2C=O. The compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde. It is stored as aqueous solutions (formalin), which consists mainly of the hydrate CH2(OH)2. It is the simplest of the aldehydes (R−CHO). As a precursor to many other materials and chemical compounds, in 2006 the global production of formaldehyde was estimated at 12 million tons per year. It is mainly used in the production of industrial resins, e.g., for particle board and coatings. Small amounts also occur naturally.
Hydrazine is an inorganic compound with the chemical formula N2H4. It is a simple pnictogen hydride, and is a colourless flammable liquid with an ammonia-like odour. Hydrazine is highly hazardous unless handled in solution as, for example, hydrazine hydrate.
Bromomethane, commonly known as methyl bromide, is an organobromine compound with formula CH3Br. This colorless, odorless, nonflammable gas is produced both industrially and biologically. It is a recognized ozone-depleting chemical. It was used extensively as a pesticide until being phased out by most countries in the early 2000s. From a chemistry perspective, it is one of the halomethanes.
Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula PH3, classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting fish, due to the presence of substituted phosphine and diphosphane (P2H4). With traces of P2H4 present, PH3 is spontaneously flammable in air (pyrophoric), burning with a luminous flame. Phosphine is a highly toxic respiratory poison, and is immediately dangerous to life or health at 50 ppm. Phosphine has a trigonal pyramidal structure.
Sterilization refers to any process that removes, kills, or deactivates all forms of life and other biological agents present in or on a specific surface, object, or fluid. Sterilization can be achieved through various means, including heat, chemicals, irradiation, high pressure, and filtration. Sterilization is distinct from disinfection, sanitization, and pasteurization, in that those methods reduce rather than eliminate all forms of life and biological agents present. After sterilization, an object is referred to as being sterile or aseptic.
Sulfuryl fluoride (also spelled sulphuryl fluoride) is an inorganic compound with the formula SO2F2. It is an easily condensed gas and has properties more similar to sulfur hexafluoride than sulfuryl chloride, being resistant to hydrolysis even up to 150 °C. It is neurotoxic and a potent greenhouse gas, but is widely used as a fumigant insecticide to control termites.
Chloropicrin, also known as PS and nitrochloroform, is a chemical compound currently used as a broad-spectrum antimicrobial, fungicide, herbicide, insecticide, and nematicide. It was used as a poison gas in World War I and during the Russian Invasion of Ukraine. Its chemical structural formula is Cl3C−NO2.
Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one hydrogen atom by an atom of iodine. It is naturally emitted in small amounts by rice plantations. It is also produced in vast quantities estimated to be greater than 214,000 tons annually by algae and kelp in the world's temperate oceans, and in lesser amounts on land by terrestrial fungi and bacteria. It is used in organic synthesis as a source of methyl groups.
Orange oil is an essential oil produced by cells within the rind of an orange fruit. In contrast to most essential oils, it is extracted as a by-product of orange juice production by centrifugation, producing a cold-pressed oil. It is composed of mostly d-limonene, and is often used in place of pure d-limonene. D-limonene can be extracted from the oil by distillation.
Aluminium phosphide is a highly toxic inorganic compound with the chemical formula AlP, used as a wide band gap semiconductor and a fumigant. This colorless solid is generally sold as a grey-green-yellow powder due to the presence of impurities arising from hydrolysis and oxidation.
This is an index of articles relating to pesticides.
The California Department of Pesticide Regulation, also known as DPR or CDPR, is one of six boards and departments of the California Environmental Protection Agency (Cal/EPA).
Inhalation is a major route of exposure that occurs when an individual breathes in polluted air which enters the respiratory tract. Identification of the pollutant uptake by the respiratory system can determine how the resulting exposure contributes to the dose. In this way, the mechanism of pollutant uptake by the respiratory system can be used to predict potential health impacts within the human population.
Dimethyl disulfide (DMDS) is an organic chemical compound with the molecular formula CH3SSCH3. It is a flammable liquid with an unpleasant, garlic-like odor. The compound is colorless although impure samples often appear yellowish.
Sulfotep (also known as tetraethyldithiopyrophosphate and TEDP) is a pesticide commonly used in greenhouses as a fumigant. The substance is also known as Dithione, Dithiophos, and many other names. Sulfotep has the molecular formula C8H20O5P2S2 and belongs to the organophosphate class of chemicals. It has a cholinergic effect, involving depression of the cholinesterase activity of the peripheral and central nervous system of insects. The transduction of signals is disturbed at the synapses that make use of acetylcholine. Sulfotep is a mobile oil that is pale yellow-colored and smells like garlic. It is primarily used as an insecticide.
Dazomet is a common soil fumigant that acts as a herbicide, fungicide, slimicide, and nematicide.
Biofumigation is a method of pest control in agriculture, a variant of fumigation where the gaseous active substance—fumigant—is produced by decomposition of plant material freshly chopped and buried in the soil for this purpose.
Angelita C. et al. v. California Department of Pesticide Regulation is an administrative complaint filed in June 1999 with the US Environmental Protection Agency about disproportionate harm to Latino children from toxic pesticides used near schools. It said that the California Department of Pesticide Regulation (CDPR) had caused discriminatory harm to Latino children when it renewed the registration for methyl bromide in January 1999 without considering the effect on nearby schools, which in some cases lay immediately adjacent to the fields.