Chemical selection and substitution warnings

Article published in the Regulator | Issue 1: 2015 

Recent environmental inspections have shown that some titleholders are using chemicals which no longer meet the standard of environmental performance required of their accepted environment plan. NOPSEMA encourages titleholders to regularly review the chemicals used in their petroleum activities to ensure environmental performance objectives are met and that impacts and risks to the environment remain at a level that is acceptable and as low as reasonably practicable (ALARP).

Chemical products are used in the oil and gas industry for many functional applications. For example, production facilities which discharge treated wastewater may require chemical additives to regulate emulsification, reduce scaling, scavenge oxygen and prevent corrosion. While criteria for selecting chemical products will include considering the desired level of engineering performance, an ongoing challenge for titleholders is balancing this need with the environmental consequence associated with usage; otherwise known as evaluating the ‘environmental performance’ of a chemical product.

Several international management systems have been established to assess the environmental performance of chemical products to inform the chemical selection process. The Offshore Chemical Notification Scheme (OCNS), managed by the Centre for Environment, Fisheries & Aquaculture Science (Cefas) in the United Kingdom, is one such example. The OCNS provides a framework and updated register which ranks the environmental performance of chemicals used in offshore petroleum activities. Many titleholders in Australia specify control measures in their environment plan that are linked to the OCNS system to ensure environmental impacts and risks associated with chemical use are managed to a level that is acceptable and ALARP.

In keeping with OSPAR Recommendations, the UK Department of Energy and Climate Change has been promoting a reduction and phase-out of hazardous chemicals through a program of identification and substitution with less hazardous chemicals. When a chemical is identified for substitution it must be either replaced, or any discharge to the marine environment must be eliminated, or its continued use and/or discharge formally justified. Substitution target dates for priority chemicals range from 31 December 2010 to 31 December 2016, depending on the assigned substitution priority level.

Titleholders should be aware that the schedule for substitution has already resulted in the reclassification or removal of several chemical products previously ranked in the OCNS database. In recent inspections, NOPSEMA has observed some titleholders using chemical products which no longer comply with the required level of environmental performance under OCNS that has been specified in their accepted environment plan.

NOPSEMA encourages titleholders to regularly review the updated OCNS chemical ranking database to ensure compliance is maintained and the discharge of hazardous chemicals to the environment is progressively reduced. Further information regarding substitution warnings may be found at

Image - Hazard ranking bands for chemical products Illustration of hazard ranking bands for chemical products classified under the OCNS system  (reproduced from