Chemical name: Methane, bromo-

Final regulatory action has been taken for the category: Pesticide, Industrial

Final regulatory action: The chemical is Banned

Use or uses prohibited by the final regulatory action:

All uses and formulations are prohibited.

Ozone depleting substances shall not be used.

The following is prohibited:

a.The manufacture of ozone depleting substances; this prohibition shall not apply to the manufacture of ozone depleting substances by means of recycling used ozone depleting substances, if ozone depleting substances are not chemically changed by this process;

b.The import and export of ozone depleting substances; this prohibition shall not apply to imports from States and exports to States which adhere to the provisions of the Montreal Protocol of 16 September 1987 (SR 814.021) to phase out Ozone Depleting Substances (hereinafter protocol), approved by Switzerland

c.The import of products and articles containing ozone depleting substances; except for products and articles, which maz be imported in accordance with the provisions of Annexes 4.9, 4.11, 4.14, 4.15 and 4.16;

dthe import of products and articles containing ozone depleting substances or manufactured using ozone depleting substances and listed in an appendix to the Protocol; subject to Letter c, this prohibition shall not apply to imports from States which adhere to the provisions of the Protocol approved by Switzerland.

Use or uses that remain allowed:

Exemptions exist for the following purposes:

a.to manufacture products or articles which may be supplied or imported in accordance with the provisions of Number 22 and Annexes 4.9, 4.11, 4.14, 4.15 and 4.16;

b.for use as intermediate products for further chemical conversion;

c.for research purposes;

d.pest control wiht a permit under Article 35 of the Ordinance on Toxic Substances of 19 September 1983 (SR 813.01)

The Federal Agency my authorize limited exemptions for other uses, provided that:

a.according to the state of the art, no replacement is available for ozone depleting substances or for the products and articles manufactured using ozone depleting substances, and

b.no more than the minimum amount of ozone depleting substances necessary for the desired purpose is used.

Pesticide use or uses that remain allowed:

None

The final regulatory action was based on a risk or hazard evaluation: Yes

Summary of the final regulatory action:

There is no registration of methyl bromide as a plant protection product.

Methyl bromide is listed as an ozone depleting substance in Annex 3.4, Number 1 of the Ordinance relating to Environmentally Hazardous Substances.

The use, production, import, and export of ozone depleting substances (as well as simple mixtures and products containing ozone depleting substances if they are in containers used solely to transport or store these substances) is prohibited.

Exception: recycled ozone depleting substances which are not chemically changed by the process

Exception: manufacture of products or articles which may be supplied or imported in accordance with the provisions of Annexes 4.9 (compressed gas containers), 4.11 (plastics), 4.14 (solvents), 4.15 (refrigerants), and 4.16 (extinguishing agents). This applies only to imports/exports from/to States which adhere to the provisions of the Montreal Protocol of 16 September 1987, and its amendments of 29 June 1990, 25 November 1992, 17 September 1997 and 3 December 1999.

The reasons for the final regulatory action were relevant to: Human health and environment

Summary of known hazards and risks to human health:

Human exposure to methyl bromide (through inhalation and skin contact) is predominantly occupational, particularly during soil or bulk fumigation, but also during manufacture. The results of inhalation studies on rats, beagles, and humans have shown that methyl bromide is rapidly absorbed through the lungs. It is also rapdily absorbed in rats following oral administration . After administration, methyl bromide or its metabolites are rapidly distributed to many tissues, including the lungs, adrenal glands, kidneys, liver, nasal turbinates, brain, testes and adipose tissue.

In a rat inhalation study, the methyl bromide concentration in tissues reached a maximum 1h after exposure, but then decreased rapidly with no traces 48 h later. The metabolism of methyl bromide has not been elucidated, although glutathione may play a role.

Methylation of proteins and lipids has been observed in tissues from several species, including humans, exposed via inhalation. Methylated DNA adducts have also been detected following in vivo and in vitro exposure of rodents or rodent cells.

In inhalation studies using [14C]-labelled methyl bromide, exhalation of ^14Co₂ ^{was the major route of elimination of 14C. A lesser amount of 14C was excreted in the urine. Following oral administration of methyl bromide urinary excretion was the major route of elimination of 14C.}

^{The central nervous system is an important target for methyl bromide. Changes in monoamine, amino acid contents and possibly catecholamine contents may be factors involved in methyl bromide-induced neurotoxicity.}

^{In 1988, the JMPR evaluated the toxicology of the bromide ion and concluded that the level causing on toxiciological effect was:}

^{Rat: 240 ppm, equivalent to 12 mg bromide/kg body weight per day}

^{Human: 9 mg bromide/kg body weight per day}

^{The acceptable daily intake (ADI) of 1 mg/kg body weight was confirmed.}

Expected effect of the final regulatory action in relation to human health:

The reduction in methyl bromide emission together with the reduction in emissions of other ozone depliting substances, is expected to reduce the risk increased UV radiation due to depletion of the stratospheric ozone ("ozone hole")

Summary of known hazards and risks to the environment:

Methyl bromide is predominantly a naturally occurring compound. Oceans are believed to be a major natural source of methyl bromide. Another source(s) may exist in the tropics, which is yet to be explained. Anthropogenic sources from fumigation and, to a much lesser extent, motor vehicles (from the combustion of organic bromine additives in leaded petrol) add to these. Present data indicate that the globally averaged atmospheric abundance of methyl bromide is between 9 and 13 pptv, equivalent to a total atmospheric loading of 150 to 220 thousand tonnes. If the atmospheric lifetime is two years (assuming only atmospheric removal processes are significant), anthopogenic sources of methyl bromide in 1990 was 69 000 tonnes, having increased at a rate of 6% per year from 1984 to 1990. About 50% of the methyl bromide produced is released into the atmosphere during, or after, use. Although methyl bromide reacts with the hydroxyl radical in the troposphere, some methyl bromide is transformed by upward diffusion to the stratosphere, where it photolyses. Active bromine species react with ozone in the lower statosphere and are partly responsible for the depletion of the ozone layer. It is estimated that anthopogenic releases of methyl bromide cause about 3% of the present total stratospheric ozone loss. Methyl bromide is used as a fungicide, partial bactericide, nematocide, insecticide, herbicide and rodenticide.

In soil, about 50% of methyl bromide is degraded by hydrolysis and microbial activity. the remainder eventually dissipates into the atmosphere. The principal degradation product is inorganic bromide, which remains as a residue in soil. Some bromide may be leached out into water or taken up by plants. Soil fumigation using methyl bromide (with 2% chloropicrin) affects both target and non-target organisms: various soil microflora and fauna are adversely affected, at least temporarily, by fumigation. High mortality of non-target insects has been noticed following fumigation under plastic covers. Methyl bromide was detected in different soil types up to 3 weeks after fumigation, the highest levels being found in the upper layers (0-40cm) of the soil.

Although methyl bromide is highly toxic for aquatic organisms, it is generally of no risk to the aquatic environment. The lowest median effect concentration (EC50) or median lethal concentration (LC50) values reported at 2.8 mg/litre for algae, 1.7 mg/litre for daphnids, and 0.3 mg/litre for fish. No-observed-effect concentrations (NOECs) in long-term studies were low (0.06 mg/litre) for daphnids and fish. Toxic concentrations are not expected to be reached under normal circumstances, because most of the methyl bromide applied on soil is degraded or lost through evaporation before it reaches surface water via run-off. In very special situations (intensive leaching of green-house soils fumigated with methyl bromide to reduce the organic bromide content), levels of methyl bromide in the mg/litre range can occur in water; concentrations of up to 9.3 mg methyl bromide/litre have been found in drainage water.

However, relatively high levels of bromide (up to 72 mg/litre) can be found in the drainage water from greenhouses and could adversely affect aquatic organisms. An EC50 value of 27 mg bromide/litre for daphnia and a lowest NOEC for different fish species of 25 mg bromide/litre were determined with long-term exposure to bromide ion.

Methyl bromide is often used in preference to other insecticides because of its ability to penetrate quickly and deeply into bulk materials and soils. Dosages for methyl bromide, as a storage fumigant, range mostly from 16 to 100 g/m3 for 2-3 days, depending on temperature. A higher dosage is required to kill eggs and pupae than adult insects. There is a variation in tolerance between different species and stages of insect and between different strains of the same insect.

There are no data on the direct effects of methyl bromide on birds and wild mammals

Ozone depletion

Methyl bromide (MB) was listed under the Montreal Protocol as an ozone depleting substance in 1992 and is listed in Annex E, Group 1. Control schedules leading to phase-out were agreed in 1995 and 1997. There are a number of concerns apart from ozone depletion that have also led countries to impose restrictions on its use. These concerns include residues in food, toxicity to humans and associated operator and public health, and detrimental effects on soil biodiversity. In some countries, pollution of surface and ground water by MB and its derived bromide ion are also concerns. Parties reported MB consumption of about 60 200 tonnes in 1998 (excluding QPS), although some sources indicated higher consumption. On the basis mainly of Ozone Secretariat data, MBTOC estimated that, for controlled uses, at least 49 170 tonnes MB was consumed in 1999 and at least 45 360 tonnes in 2000. Although the data set is incomplete, the data at country level indicates MB consumption has been reduced in non-Article 5(1) countries in line with the Protocol requirements. Controlled MB consumption in Article 5(1) countries rose from about 8 460 tonnes in 1991 to about 17 600 tonnes in 1998, representing an increase of 15% per year on average. However, since 1998 the consumption has decreased at an average rate of about 5% per year (1998-2000). Based on Ozone Secretariat data reported so far, MBTOC estimated the total Article 5(1) MB consumption to be around 16 440 tonnes in 2000. Between 1998 and 2000, national MB consumption fell by more than 20% in some Article 5(1) countries, but increased significantly in others.

Under current usage patterns, the proportions of applied MB eventually emitted to the atmosphere are estimated by MBTOC to be 40-87%, 85-98%, 69-79% and 90-98% of applied dosage for soil, perishable commodities, durable commodities and structural treatments respectively. These figures, weighted for proportion of use and particular treatments, correspond to a range of 50 - 87% overall emission from agricultural and related uses, with a best estimate of overall emissions of 73%, or 40 515 metric tones based on production of 55 500 tonnes in 2000.

The current control measures, agreed by the Parties at their ninth Meeting in Montreal in September 1997, can be paraphrased as:

For non-Article 5(1) Parties operating under the Protocol (developed countries) a 25% cute in production and consumption, based on 1991 levels, from 1 January 1999, a 50% cut from 1 January 2001, a 70% cut from 1 January 2003 and phase out by 1 January 2005 with provisions for exemptions for any critical uses. A freeze on MB production and consumption based on 1991 levels already applies from 1 January 1995.

Emissions from fumigation operations occur through leakage and permeation during treatment (inadvertent emissions) and from venting at the end of a treatment (intentional emissions). Estimates of the proportion of MB used that is released into the atmosphere vary widely because of: differences in usage pattern; the condition and nature of the fumigated materials; the degree of gas-tightness; and local environmental conditions. Some MB may also be converted to non-volatile materials making it incorrect to equate production with emissions.

Expected effect of the final regulatory action in relation to the environment:

The reduction in methyl bromide emission together with the reduction in emissions of other ozone depliting substances, is expected to reduce the risk increased UV radiation due to depletion of the stratospheric ozone ("ozone hole")

Date of entry into force of the final regulatory action: 01/01/1996