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Methyl bromide passes its sell-by date

22nd May 2006

More than 5,000 farms and organisations joined forces with the United Nations Environment Programme (UNEP) in April to reinvigorate the phase-out of an agricultural fumigant that damages the ozone layer. Two UK supermarket chains were specifically highlighted in the UNEP publicity for taking a lead role – Marks & Spencer and the Co-op.

Methyl bromide is a toxic gas and pesticide, used since the 1940s to kill insects and rodents in some mills and food factories. It is also used to kill a wide spectrum of pests in soil before farmers plant out strawberries or other high-value crops prone to pest damage.

When the ozone layer thins, living systems are increasingly exposed to damaging ultraviolet radiation. Scientists have noted the rapid rise in incidence of skin cancer in Europe. Cancers related to sun and ultraviolet exposure are predicted to double in parts of northern Europe by 2015 – partly due to sunbathing habits, and partly due to a thinner ozone layer. Higher ultraviolet exposure (UV-B) also disrupts the timing and growth of certain types of crops and forest trees, and can reduce fish stocks.

As well as methyl bromide, ozone-damaging chemicals also include CFCs (used in older fridges and air-conditioning) and halons (used in fire extinguishers).
Methyl bromide was added to the official international list of ozone-damaging chemicals in 1992 and subsequently all governments agreed to phase it out, under an agreement called the Montreal Protocol. All industrialised countries, including the UK, were scheduled to phase out methyl bromide by January 2005.

A masked operator with a cannister of methyl bromideContinued application worldwide: An operator from an Indonesian pest-control company prepares to fumigate with the ozone-damaging pesticide methyl bromide. According to the company website, clients include hotels, supermarkets and food manufacturers.

By 2003 about 56 countries that had previously used methyl bromide in the past no longer used it, and others appeared to be well on track to meet the scheduled phase-out date. Use of methyl bromide reduced from over 56,000 tonnes in 1991 to about 14,500 tonnes in 2003 in industrialised countries (a 74% reduction).

The UK reduced consumption from about 630 tonnes in 1991 to about 167 tonnes in 2003 (73% reduction). Former methyl bromide users have adopted other successful pest control methods.

However, some mills, food companies and farmers in Europe and the US did not want to stop using methyl bromide. Manufacturers and food industry/agriculture groups claimed that no technically and economically feasible substitutes were available, despite growing evidence of the negative impact of the chemcial’s use on human health were emerging. As a result some exemptions were granted by governments. In the UK in 2006, Methyl Bromide is still permitted for:

Some treatment of buildings – mills (e.g. flour mills), food processing factories (producing products such as biscuits, cereals, snack foods, spice ingredients) and cheese stores;
Some treatment of food items such as nuts, dried fruit, herbs, spices and rice;
Some soil treatments for strawberries, raspberries and ornamental tree nurseries.
The Association of Cereal Food Manufacturers and other food companies have applied to extend exemptions in future years. Methyl bromide users claim that their own individual use is so small that it cannot do any significant harm the earth’s protective shield, neglecting to take into account the cumulative environmental effect.

The farms and companies that have joined UNEP’s partnership have already stopped using methyl bromide or will pledge to halt its use by September 2007. As noted above, the partnership includes two UK supermarkets – Marks & Spencer and the Co-op – but has yet to attract support from the likes of Tesco, Sainsbury's or Asda.

Although the quantity of methyl bromide detected in the atmosphere has fallen significantly since 1998, UNEP says that ‘scientists have warned against complacency – many small, remaining uses of methyl bromide risk negating the gains achieved to date’. UNEP also warns that ‘the ozone layer will not recover if the Montreal Protocol phase-out commitments are not implemented in full’.

The reality is that many small uses add up to a big problem for the ozone layer – and that could lead to a very big problem for all of us.

Useful resources

Pesticides Action Network Europe