Methyl bromide is a fumigant used to control pests in agriculture and shipping. Methyl bromide also depletes the ozone layer. Therefore, along with other countries, the United States has phased out production and consumption of methyl bromide with important exceptions for critical uses as well as quarantine and preshipment. Learn more about protecting the ozone layer.
What Is Methyl Bromide?
Methyl bromide is an odorless, colorless gas used to control a wide variety of pests in agriculture and shipping, including fungi, weeds, insects, nematodes (or roundworms), and rodents.
Agricultural growers inject methyl bromide about two feet into the ground to sterilize the soil before crops are planted. Although the soil is covered with plastic tarps immediately after a treatment, 50 to 95 percent of the methyl bromide eventually enters the atmosphere. Learn more about soil fumigants.
Methyl bromide is also used to treat commodities such as grapes, asparagus, logs, and other imported goods to prevent introducing pests to the United States. Treatments often fulfill official quarantine requirements for international shipments.
Methyl bromide is a toxic substance. Because it dissipates rapidly to the atmosphere, it is most dangerous at the fumigation site. Human exposure to high concentrations of methyl bromide can cause central nervous system and respiratory system failures and can harm the lungs, eyes, and skin.
Methyl bromide damages the ozone layer
In the atmosphere, methyl bromide depletes the ozone layer and allows increased ultraviolet radiation to reach the earth's surface. Methyl bromide is a Class I ozone-depleting substance (ODSODSA compound that contributes to stratospheric ozone depletion. ODS include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), halons, methyl bromide, carbon tetrachloride, hydrobromofluorocarbons, chlorobromomethane, and methyl chloroform. ODS are generally very stable in the troposphere and only degrade under intense ultraviolet light in the stratosphere. When they break down, they release chlorine or bromine atoms, which then deplete ozone. A detailed list (http://www.epa.gov/ozone/science/ods/index.html) of class I and class II substances with their ODPs, GWPs, and CAS numbers are available.), as defined by the Montreal Protocol on Substances that Deplete the Ozone Layer.
Find more information on methyl bromide:
- EPA's Office of Air Quality Planning & Standards Air Toxics Website: Methyl Bromide (Bromomethane)
- EPA Integrated Risk Assessment of Methyl Bromide
The Phaseout of Methyl Bromide
The amount of methyl bromide produced or imported was reduced incrementally until it was phased out on January 1, 2005. Certain uses of methyl bromide are exempt from this phaseout. These include:
- Critical uses
- Quarantine and preshipment uses
Methyl Bromide Alternatives
Both chemical and non-chemical alternatives to methyl bromide exist. In most cases, these alternatives can manage the pests previously controlled with methyl bromide. For example, steam sterilization of soil is a viable alternative to using chemical fumigants for certain pests and soil types. Also, harvesters can use integrated pest management techniques, as well as pheromone, electrocution, and light traps, to manage or monitor pest populations.
Alternatives research is ongoing, and EPA continues to prioritize the registration of alternatives to methyl bromide.
- Proceedings from the Annual Methyl Bromide Alternatives Outreach Conference Exit
- U.S. Department of Agriculture, Agricultural Research Service (Crop Protection & Quarantine Research)
- U.S. Department of Agriculture, Agricultural Research Service (Plant Disease Research)
- Alternatives for Specific Commodities
Methyl Bromide Critical Uses
Methyl bromide users can apply for a critical use exemption. EPA rulemakings and the decisions of the Parties to the Montreal Protocol authorize the critical uses of methyl bromide. The use of methyl bromide is deemed “critical” only if it meets the following criteria:
- Lack of methyl bromide availability would result in a significant market disruption.
- No technically and economically feasible alternatives or substitutes are available.
A nomination does not guarantee that these uses will be authorized. Nominations must go through EPA’s official rulemaking process and be authorized by the Parties to the Montreal ProtocolMontreal ProtocolThe international treaty governing the protection of stratospheric ozone. The Montreal Protocol on Substances That Deplete the Ozone Layer and its amendments control the phaseout of ODS production and use. Under the Montreal Protocol, several international organizations report on the science of ozone depletion, implement projects to help move away from ODS, and provide a forum for policy discussions. In addition, the Multilateral Fund provides resources to developing nations to promote the transition to ozone-safe technologies. The full text of the Montreal Protocol (http://ozone.unep.org/Publications/MP_Handbook/Section_1.1_The_Montreal_Protocol/) is available from the United Nations Environmental Programme (UNEP)..
Methyl Bromide for Quarantine and Preshipment
A separate exemption under the Montreal Protocol and the Clean Air Act allows the production and consumption of methyl bromide for quarantine and preshipment (QPS) purposes.
Quarantine fumigation prevents the introduction of specific quarantine pests into a defined geographical area, such as an importing country. Quarantine treatments must meet the requirements of the USDA's Animal and Plant Health Insepction Service (APHIS) treatment manual or the listed treatments compiled by the National Plant Board. An example of a quarantine application of methyl bromide is the fumigation of logs to control wood-boring pests.
Methyl bromide may be used fumigate commodities within 21 days of export to meet the official requirements of the importing or exporting country. An example of a preshipment use of methyl bromide is the application to exported nuts immediately before shipment because of official requirements of the destination country.
QPS methyl bromide may not be used in residential structures or in public food service facilities such as restaurants.
Distributors and applicators of QPS methyl bromide have reporting and recordkeeping requirements. The form can be found on the recordkeeping and reporting page.
See the complete QPS rule: Protection of Stratospheric Ozone: Process for Exempting Quarantine and Preshipment Applications of Methyl Bromide (January 2, 2003, 68 FR 238).
Apply for a Methyl Bromide Critical Use Exemption
Applications for critical use exemptions are due September 15th every year. The U.S. government reviews the applications and seeks authorization for those uses from the Parties to the Montreal Protocol if they meet the critical use criteria. View the notice in the Federal Register describing information needed in an application.
Once the Parties authorize critical uses and an amount of methyl bromide for those critical uses, EPA publishes a rule allowing for the production of critical use methyl bromide. Each round of application and review takes three years.
Download the application forms below.
Pre-plant application form
- Application form for pre-plant sectors (PDF version)
Post-harvest application form
- Application form for post-harvest application form (PDF version)
Methyl Bromide Reporting Forms
Most transactions involving methyl bromide (e.g., production, transfer, sale) must be reported to EPA. If you are not sure if you need to report to EPA, please contact us.
Methyl bromide reporting forms are due 45 days after the end of the quarterly reporting period. Certification forms for the order/purchase of methyl bromide for critical uses or QPS applications do not need to be submitted to EPA.
For methyl bromide laboratory suppliers: Please use the Class I Laboratory Supplier Quarterly Report to report on the amount of methyl bromide purchased from producers and/or importers and sold to laboratory customers.