Dazomet (ISO)

Fires involving this material can be controlled with a dry chemical, carbon dioxide or Halon extinguisher. (NTP, 1992)

Use water spray, powder, foam, carbon dioxide.

Fresh air, rest.

Remove contaminated clothes. Rinse skin with plenty of water or shower.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Refer for medical attention .

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

Store in cool, dry place out of children's reach.

/Store/ separated from acids, food and feedstuffs. Cool. Dry. Keep in a well-ventilated room.

SMALL SPILLS AND LEAKAGE: If a spill of this chemical occurs, FIRST REMOVE ALL SOURCES OF IGNITION, then you should dampen the solid spill material with acetone and transfer the dampened material to a suitable container. Use absorbent paper dampened with acetone to pick up any remaining material. Seal your contaminated clothing and the absorbent paper in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with acetone followed by washing with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

EPA has developed a multi-faceted approach to addressing bystander and handler risk for fumigants. This involves label changes, education of fumigant applicators and handlers, monitoring of fumigant air concentrations, and development of additional data to refine risk assessments.

Specific mitigation for bystanders and handlers from soil use of dazomet includes: (1) Maximum Rate Reduction - A change in the maximum application rate will be a reduction from 530 to 425 lbs a.i./A, which will directly reduce the potential risks to both humans and non-target organisms. (2) Restricted Use Pesticide (RUP) Classification - MITC, the byproduct of dazomet, meets the criteria for restricted use based on human hazard criteria and exposure incidents. All soil fumigant products containing dazomet will be RUPs. (3) Buffer Zones - Buffer zones, of varying sizes based on application method, application rate, and application block size, and emission control measures are required. Buffer zones will be in effect from the time the fumigation begins until 48 hours following the application. (4) Posting - EPA is requiring that buffer zones be posted at usual points of entry and along likely routes of approach to the buffer unless (a) a physical barrier such as a fence prevents access to the buffer, or (b) all of the area within 300' of the buffer is under the control of the owner/operator. The posting requirement is intended to prevent passersby from entering a buffer zone.

Posting is recognized as an effective means of informing workers and others about areas where certain hazards and restrictions exist. Current soil fumigant labels require treated areas to be posted, and handlers are required to wear specific PPE when they are in a treated area. For buffer zones to be effective risk mitigation, bystanders, including agricultural workers in nearby areas, need to be informed of the location and timing of the buffer to ensure they do not enter areas designated as part of the buffer zone. In addition to alerting bystanders, posting a buffer zone will help handlers determine where and when they are required to use PPE. ...

Mandatory Good Agricultural Practices (GAPs) must be followed during all soil applications. GAPs specify appropriate weather conditions, injection depth, soil sealing, use of tarps, soil temperature, air temperature, soil moisture, soil preparation, prevention of end row spillage, flushing of drip irrigation lines, and calibration, set-up, repair and maintenance of application equipment.

For more Preventive Measures (Complete) data for DAZOMET (12 total), please visit the HSDB record page.

LC50 Anas platyrhynchos (Mallard duck, age 13 days) diet >5000 ppm for 8 days

LC50 Colinus virginianus (northern bobwhite, age 12 days) diet 1850 ppm for 8 days (95% confidence interval: 1028-3330 ppm)

LC50 Colinus virginianus (northern bobwhite, age 11 days) diet 2300 ppm for 8 days (95% confidence interval: 1562-3837 ppm)

LD50 Colinus virginianus (northern bobwhite) oral 415 mg/kg (95% confidence interval: 314-548 mg/kg)

For more Ecotoxicity Values (Complete) data for DAZOMET (30 total), please visit the HSDB record page.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 52(SRC), determined from a log Kow of 0.63(2) and a regression-derived equation(3), indicates that dazomet is expected to have high mobility in soil, however it is expected to hydrolyze(2) before extensive leaching occurs(SRC). Volatilization of dazomet from moist soil surfaces is not expected to be an important fate process(SRC) given a Henry's Law constant of 2.66X10-10 atm-cu m/mole(2). When dazomet is applied to soil, either to the surface or incorporated, it quickly hydrolyzes in the presence of moisture(4). The major degradate is methyl isothiocyanate, but formaldehyde, monomethylamine, hydrogen sulfide and (in acid soils) carbon disulfide, are also formed(4). The half-life of dazomet in soil has been reported as less than 1 day (pH >5)(2). The rate of disappearance was found to be the same in both unamended and sterilized soils(5) and in different soil types(6), indicating that chemical hydrolysis and not biodegradation is the primary removal process. Dazomet is not expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 2.80X10-6 mm Hg(2).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 52(SRC), determined from a log Kow of 0.63(2) and a regression-derived equation(3), indicates that dazomet is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon a Henry's Law constant of 2.66X10-10 atm-cu m/mole(2). In water, dazomet is expected to rapidly undergo hydrolysis, forming methyl isothiocyanate and formaldehyde(4). Half-lives of 3.6, 2.4, 2.8, and 4.0 hours have been reported at pH values of 4.4, 5.7, 7.0, and 8.0, respectively(5). In salt water (0.15 M), a half-life of 6.1 hours was reported(5). According to a classification scheme(6), an estimated BCF of 2.4(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), dazomet, which has a vapor pressure of 2.80X10-6 mm Hg at 20 °C(2), will exist in both the vapor and particulate phases in the ambient atmosphere. Vapor-phase dazomet is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 1.4 hours(SRC), calculated from its rate constant of 2.85X10-10 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). Particulate-phase dazomet may be removed from the air by wet or dry deposition(SRC). It may undergo hydrolysis during rain events or in clouds(SRC) due to degradation on contact with moisture(2). It has been suggested that dazomet may also undergo direct photolytic degradation and this process may contribute to atmospheric removal(4).

/BIRDS and MAMMALS/ The NOEC /for bobwhite quail/ is 147 mg/kg with observed effects at higher dose(s) including lethargy, anorexia, and reduced mean body weights and feed consumption. Based on these results, dazomet is categorized as moderately toxic to avian species on an acute oral basis.

/BIRDS and MAMMALS/ Avian reproduction studies ... are required for dazomet because birds may be subject to repeated or continuous exposure to the pesticide, especially preceding or during the breeding season. The preferred test species are mallard duck and bobwhite quail. Significant treatment-related effects in the mallard study included reductions in egg production, egg quality, fertility, and embryonic survival at the 1000 ppm level. A significant reduction in hatchling weight was also observed at the 100 ppm level. In the bobwhite quail study, dazomet exposure of 100 ppm significantly reduced the number of hatched to eggs laid and the proportion of live embryos to viable embryos was significantly reduced at all treatment levels. At the 1000 ppm level, egg fertility, embryonic survival, hatchability, and chick survival were adversely affected.

/AQUATIC SPECIES/ Based on the rapid hydrolysis of dazomet, aquatic organisms will likely be exposed only to MITC (methyl isothiocyanate)... .

/AQUATIC SPECIES/ Freshwater fish acute studies for the degradate (MITC) indicate that it is very highly toxic to rainbow trout with 96-hour LC50 values ranging from 0.094 to 0.0512 ppm. MITC is also highly toxic to bluegill sunfish with a reported 96-hour LC50 of 0.142 ppm. Based on the rapid hydrolysis of dazomet, aquatic organisms will likely be exposed only to MITC; consequently, acute risk to freshwater fish species will be assessed using the lowest toxicity value from these studies (rainbow trout LC50 of 0.0512 ppm; static renewal test). /Methyl isothiocyanate/

For more Ecotoxicity Excerpts (Complete) data for DAZOMET (6 total), please visit the HSDB record page.

The Koc of dazomet is estimated as 52(SRC), using a log Kow of 0.63(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that dazomet is expected to have high mobility in soil; however it is expected to hydrolyze(1) before extensive leaching occurs(SRC).

/SIGNS AND SYMPTOMS/ Even dilute soln cause skin irritation and sensitization in humans.

/SIGNS AND SYMPTOMS/ Not readily absorbed through skin. May cause skin irritation. Inhalation of dusts or powders may result in nonspecific irritation of the upper respiratory tract.

/SIGNS AND SYMPTOMS/ Ingestion may produce symptoms of nonspecific irritation of the GI tract, nausea, vomiting, cramps and diarrhea. In severe cases, CNS depression may result.

/SIGNS AND SYMPTOMS/ ... human exposures to MITC are consistent with exposure to an irritant and include: eye effects--watery, burning, and itchy eyes, blurred vision; skin effects -rash, burns, redness, swelling; systemic effects-nausea, chest pain, scratchy throat, diarrhea, weakness, dizziness, headache, malaise, salivation, vomiting; and respiratory effects-cough, shortness of breath. With respect to respiratory impairment, arguably, eye irritation is less severe compared to other possible effects associated with inhalation exposure to MITC, particularly given the expected reversible nature of the eye irritation effects at lower concentrations. Nonetheless, eye (as well as nose and throat) irritation is uncomfortable and could potentially interfere with everyday tasks or activities. /MITC/

/CASE REPORTS/ A case of allergic contact dermatitis resulting from exposure to dazomet was described. The patient was an English paper mill worker with a 3 mo history of sore, itchy upper and lower eyelids accompanied by erythema and scaling. The reactions usually /resulted/ 4 hr after finishing work and lasted for at least 24 hr. The reactions first appeared after the paper mill changed biocides to Busan-79 and Busan-1058. Patch testing produced negative results for Busan-79, but a moderately strong positive reaction with Busan-1058. Busan-1058 was known to contain 24% dazomet as the active ingredient. Once the paper mill discontinued using dazomet as a biocide, the patient's dermatitis disappeared. ...

Dazomet's production may result in its release to the environment through various waste streams; its use as a soil sterilant, nematicide, fungicide, slimicide in pulp and paper manufacture, and as a preservative in adhesives and glues(1) will result in its direct release to the environment(SRC).

AEROBIC: Dazomet, present at 100 mg/L, reached 4% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test(1). The rate of disappearance of dazomet from both an unamended and sterilized Williamson silt loam was identical, indicating that the initial phase of degradation in soil occurred predominantly from nonenzymatic mechanisms(2). The rate of degradation of dazomet in soil, as measured by the release of methyl isothiocyanate, was found to be independent of the soil microorganisms present(3).

Based on a review of the dazomet database and public comments on the Agency's assessments for dazomet, the Agency has sufficient information on the human health and ecological effects of dazomet to make decisions as part of the reregistration process under FIFRA. The Agency has determined that dazomet products are eligible for reregistration provided that (i) required product specific data are submitted, (ii) the risk mitigation measures outlined in this document are adopted, and (iii) label amendments are made to implement these mitigation measures, as outlined in Chapter V.

As the federal pesticide law FIFRA directs, EPA is conducting a comprehensive review of older pesticides to consider their health and environmental effects and make decisions about their continued use. Under this pesticide reregistration program, EPA examines newer health and safety data for pesticide active ingredients initially registered before November 1, 1984, and determines whether the use of the pesticide does not pose unreasonable risk in accordance to newer saftey standards, such as those described in the Food Quality Protection Act of 1996. Pesticides for which EPA had not issued Registration Standards prior to the effective date of FIFRA '88 were divided into three lists based upon their potential for human exposure and other factors, with List B containing pesticides of greater concern than those on List C, and with List C containing pesticides of greater concern than those on List D. Tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione is found on List B. Case No: 2135; Pesticide type: fungicide, herbicide, antimicrobial; Case Status: OPP is reviewing data from the pesticide's producers regarding its human health and/or environmental effects, or OPP is determining the pesticide's eligibility for reregistration and developing the Reregistration Eligibility Decision (RED) document.; Active ingredient (AI): Tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione; Data Call-in (DCI) Date(s): 06/14/91, 05/22/92, 10/13/95; AI Status: The producers of the pesticide has made commitments to conduct the studies and pay the fees required for reregistration, and are meeting those commitments in a timely manner.

Used as a biocide in pulp and paper mills; also used as a soil disinfectant in farming; [Kanerva, 1776] Used as a biocide in paints; [Adams, p. 475]

Pulp and Paper Processing [Category: Industry]

For Dazomet (USEPA/OPP Pesticide Code: 035602) ACTIVE products with label matches. /SRP: Registered for use in the U.S. but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./

Soil sterilant, applied prior to planting out crops. Controls soil fungi..., nematodes, germinating weed seeds, bacteria, and soil insects. Also used as a slimicide in pulp and paper manufacture, and as a preservative in adhesives and glues.

Preservative for proteinaceous additives

Preplant control of soil fungi, nematodes, bacteria, germinating weeds, soil insects in seedbeds for tobacco, nurseries, greenhouses, substrates for potted plants, turf, ornamentals, vegetables.

(1970) 5.53X10+8 GRAMS

(1975) 4.54X10+7 GRAMS (CONSUMPTION)

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#3390]

Prepared commercially by reaction of carbon disulfide, methylamine and caustic soda.

Dazomet may be produced by: (A) The interaction of carbon disulfide, methylamine and formaldehyde; or (B) The action of formaldehyde on methylammonium methyldithiocarbamate.

Metam-sodium + formaldehyde + methylamine (carbonyl condensation)

THE TECHNICAL GRADE IS GREATER THAN OR EQUAL TO 98% PURE. ...`BASAMID', GRANULAR (980-1000 G/KG).

Granule, dispersible powder, wettable powder

Granule, greater than or equal to 94% pure

Pelleted/tableted, liquid (soluble concentrate and flowable concentrate) solutions, water soluble packaged solids, ready to use solutions.

Insecticides, Fungicides, Herbicides

Environmental transformation -> Pesticides (parent, predecessor)

2H-1,3,5-Thiadiazine-2-thione, tetrahydro-3,5-dimethyl-: ACTIVE

The WHO Recommended Classification of Pesticides by Hazard identifies Dazomet (technical grade) as Class III: slightly hazardous; Main Use: herbicide.

Dazomet, by virtue of the release of methyl isothiocyanate, is a soil fumigant effective for control of nematodes, germinating weeds and soil fungi, such as: fusarium, pythium, rhizoctonia, and verticillium spp and colletotrichum atramentarium, when incorporated into glasshouse soils at 400-600 kg ai/ha. At these rates it is also effective against millipedes, soil insects and wireworms. It is strongly phytotoxic and treated soils should not be planted until shown to be free of the cmpd and its decomp prod, generally within 8-24 days (depending on soil temp) by the normal germination of cress seed sown on a sample of the treated soil. The granular formulation is also recommended for outdoor use at 200-400 kg/ha depending on soil type; soil temp should be at least 7 °C at a depth of 15 cm, the granules incorporated evenly to a depth of 20-22 cm and surface of the treated soil sealed with polythene, by flooding with water or by compaction with a heavy roller to compact the surface. Cultivation is needed to aid release of the methyl isothiocyanate and the cress test should be applied...

SOIL DISINFECTION WITH DAZOMET (50 G/SQ M) INCREASED PLANT GROWTH AND THE NUMBER OF CUT FLOWERS PRODUCED BY CARNATIONS (DIANTHUS CARYOPHYLLUS) IN GREENHOUSE EXPT.

There are several potential sources in the environment of MITC including metam sodium, metam potassium, and dazomet. In many situations, data have been used that provide results for MITC, but the sources cannot be determined (e.g., levels in ambient air). Following application of dazomet, MITC can volatilize into the atmosphere and be transported off-site. This can lead to exposures to MITC in the general public and to workers following application of dazomet.