The Oil Care Campaign was set up in 1995 by the Environment Agency to provide guidance on the safe management of oil. The campaign includes representatives from the Environment Department (DEFRA) and industry including Shell, the UK Petroleum Industry Association and the Federation of Petroleum Suppliers.
The regulations require tanks to be fitted with secondary containment to contain any spill. New oil stores had to comply in 2002, existing stores near a watercourse in 2003 and most remaining oil stores by September this year. DEFRA exempted most oil tanks serving private households from the regulations.
DEFRA expects that the regulations will cut the total number of water pollution incidents caused by oil pollution to around 2,600 in 2005, based on data collected by the Agency.
The Oil Care Campaign's report suggests that the regulations are having an effect - but that DEFRA's target is in danger of being missed. The number of oil pollution incidents fell from almost 5,700 in 2001 to 4,650 in 2003.
However, the true number of oil spills may be much higher than indicated by Agency data, which is based on incidents reported by the public.
Researchers analysed insurance data from oil distribution companies and data from a survey of accredited spillage contractors. They found that over 70% of major pollution incidents are not reported to the Agency.
The report says the main reason for under-reporting is that many spills are dealt with by spillage contractors and are contained on land. Spills entering a watercourse are more likely to be reported to the Agency.
The research also found that domestic oil stores - most of which are not covered by the regulations - were by far the greatest source of oil pollution, accounting for 12% of all major incidents recorded by the Agency in 2003.
Most spills occur because of split tanks, overfilling or pipe failure. Single skin plastic tanks are at most risk of splitting - and are widely used by private households where secondary containment is rare.
The Oil Care Campaign has been criticised by the Environmental Industries Commission, which represents companies in the pollution control sector, for weakening the report's original recommendations.
According to the EIC, a draft of the report made clear recommendations, including the introduction of a certification scheme to ensure oil storage tanks are fit for purpose and amending the building regulations to require secondary containment on all but the lowest risk sites.
In the published report, these recommendations have been replaced by "discussion points" seeking views on whether these improvements should be introduced.
EIC director Merlin Hyman said: "It is disappointing that the Oil Care Campaign has seen fit to weaken this report...Oil spills cause massive damage to the environment and we will never tackle them if serious recommendations are swept under the carpet."
Richard Martin, the Agency's Oil Care Campaign manager, said he was disappointed by the EIC's position. He confirmed the changes had been made following comments from oil industry representatives who had concerns over the practicalities of the original recommendations.
The final report recommends that the Campaign should investigate how the Agency's data on spills could be improved. The group will also investigate options for improving oil storage.