Substitution of hazardous offshore chemicals in UK waters: an evaluation of their use and discharge from 2000 to 2012

Abstract

The offshore oil and gas industry will use and discharge large quantities of chemicals into the marine environment during operational activities, with some of those chemicals considered hazardous. Chemical substitution, as part of the environmental regulatory regime, has been advocated as a simple and effective tool to reduce inputs of hazardous substances to the environment. In 2007 the UK National Plan was introduced, to prioritise into four groups and subsequently phase out in stages the most hazardous substances used and discharged during offshore oil and gas operations. Level 1 substances categorised for phase out in 2010 were virtually eliminated from discharge between 2006 and 2012 and there was a significant decline in discharge of substances at Level 2 to 4 over the same period. The discharge of substitutable substances had been reduced to less than 5 tonnes at most production installations by 2012. More than 91% of this discharge is contributed by corrosion inhibitor, scale inhibitor, demulsifier and water clarifier formulations. The discharge of corrosion inhibitors accounted for the largest contribution to UK National Plan Level 2 substitutable substance discharges, and they appear to be the type of product with the fewest options found for substitution. This implies that a finite discharge of substances from these groups will continue to require formal justification beyond the target date, as occurred for Level 1 substances after the 2010 target date. The overall figures for substitutable substance discharges from 2006 to 2012 suggest that the introduction of the UK National plan with prioritisation of substances for substitution and ongoing encouragement of operators and, indirectly, suppliers to work towards reduction goals for substitutable substances is resulting in a reduction in discharges and contributing to their ultimate phase out. The next few years will be particularly challenging as the deadline for the phase-out of discharges of substitutable substances included in OSPAR Recommendation, 2006/3 is 1 January 2017 and, in addition, by 2018 all chemical substances used offshore will need to have been registered under the EC REACH Regulation. The approach described in this paper illustrates the benefits of a prioritised strategy for chemical substitution and an ongoing dialogue between the industry and regulator. A continuing case by case dialogue with offshore operators and suppliers will be essential to ensure that alternative technical solutions are trialled and options for substitution are investigated at the earliest stage.