Why is Methyl Bromide being phased out?
Why is Methyl Bromide being phased out?
The Montreal Protocol of 2004 ratified that methyl bromide use would be phased out globally. Methyl Bromide is one of the substances to have a significant effect on the depletion of 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. This includes fungi, weeds, insects, nematodes (roundworms) and rodents.
Agricultural growers inject methyl bromide about half a meter into the ground to sterilize the soil before crops are planted. The soil is covered with plastic tarps immediately after a treatment but 50 to 95 percent of the methyl bromide eventually enters the atmosphere.
Methyl bromide is a toxic substance. It is most dangerous at the fumigation site because it dissipates rapidly into the atmosphere. 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.
The Montreal Protocol
Methyl bromide is mainly used for the fumigation of commodities in stacks, bins and soils that are urgently needed in the food and beverage industry It plays an important role in the emergency treatment of incoming stock and pest-infested areas.
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 (ODS), as defined by the Montreal Protocol on Substances that Deplete the Ozone Layer.
The Phaseout of Methyl Bromide
It was determined at The Montreal Protocol of 2004 that developed countries would incrementally phase out the use of methyl bromide by January 2005. Developing nations were given a target to implement the same by 2015.
In March 2012, the South African Department of Agriculture, Forestry and Fisheries warned that, owing to increased international pressure to ban the use of the fumigant worldwide, they could not guarantee methyl bromide’s availability past 2015.
The global decrease in demand for methyl bromide (as a result of its phasing out) reduced production capacity of the fumigant. This inflated the costs of fumigation using the product.
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. Harvesters can also use integrated pest management techniques as well as pheromone, electrocution and light traps to manage or monitor pest populations.
Although originally manufactured for use in structural fumigations, Sulfuryl Fluoride (ProFume) has proved an effective chemical alternative to methyl bromide across numerous applications in the postharvest sphere. This includes pests resistant to phosphine.
ProFume has also gained acceptance in some global markets for quarantine applications. Douglas Products continue to test and register proven applications of sulfuryl fluoride (ProFume/Vikane) worldwide.
Methyl Bromide going forward.
Methyl bromide users can apply for a critical use exemption. In California, USA, strawberry harvesters significantly reduced the use of methyl bromide but have since used the critical use exemption application to incrementally increase methyl bromide use again. The state still records a 50% reduction in methyl bromide use, but numbers can improve.
The 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.
Sulfuryl Fluoride was first used in South Africa in April 2019. It’s proven efficacy against a broad spectrum of pests in all life stages has shown it to be a viable alternative to methyl bromide. Its application and success continues to develop. This means the phase out of methyl bromide can be now be implemented.
