About OCNS

The Offshore Chemical Notification Scheme (OCNS) manages chemical use and discharge by the UK and Netherlands offshore petroleum industries. The scheme is regulated in the UK by the Department of Energy and Climate Change (DECC) using scientific and environmental advice from Cefas and Marine Scotland. In the Netherlands the State Supervision of Mines (SSM) regulates the scheme with scientific and environmental advice from Cefas and Netherlands government agencies.

The OCNS applies to all chemicals, which are used in the actual exploration, exploitation and associated offshore processing of petroleum on the UK Continental Shelf.

The OCNS therefore applies to those "operational" chemicals/products* which through their mode of use are expected in some proportion to be discharged e.g. rig washes, pipe dopes, jacking greases and hydraulic fluids used to control wellheads and blow-out preventers. As well as those chemicals used in the actual production of hydrocarbons, chemicals generated offshore (such as sodium hypochlorite) must also be notified. Default product templates for these types of chemicals are available on the downloads page.

*N.B. The word 'chemicals' when used subsequently refers to fully formulated products used offshore whether these are comprised of one or more distinct chemical substances.

The scheme does not apply to chemicals that might otherwise be used on a ship, helicopter or other offshore structure. This effectively exempts, for example, products used solely within domestic accommodation areas, additives to potable water systems, paints and other coatings, fuels, lubricants, fire-fighting foams, hydraulic fluids used in cranes and other machinery etc. If there is any doubt as to whether or not a chemical should be included in a UK risk assessment, then operators are advised to consult the DECC or Cefas. All queries regarding risk assessment in the Netherlands should be directed to SSM

Cefas has had a long involvement with the regulation of offshore chemicals. The OCNS was originally introduced by the UK in 1979. In 1993, the UK Government introduced a revised scheme, which classified chemicals using test protocols approved by the Oslo and Paris Commissions (OSPAR). This was modified in detail, in early 1996, to meet the requirements of the OSPAR Harmonised Offshore Chemical Notification Format (HOCNF) which co-ordinates the testing requirements for oilfield chemicals throughout the NE Atlantic sector. In 2007 the Netherlands Government appointed Cefas as administrators for their HMCS system based on the same OSPAR guidelines.

The Combined Netherlands and UK OCNS is based upon OSPAR Decision 2000/2 on a Harmonised Mandatory Control System for the Use and Reduction of the Discharge of Offshore Chemicals.

At the heart of OSPAR Decision 2000/2 are two Recommendations.

• Recommendation 2008/1 amending recommendation 2000/4 on a Harmonised Pre-Screening Scheme for Offshore Chemicals, which facilitates the substitution of chemicals with certain characteristics by less hazardous alternatives
• Recommendation 2008/2 amending Recommendation 2000/5, which introduced some changes to the Harmonised Offshore Chemical Notification Format (HOCNF) and to its Guidelines

Decision 2000/2 and its supporting Recommendations entered into force on 16 January 2001. The Decision requires offshore chemicals to be ranked according to their calculated Hazard Quotients (HQ - ratio of Predicted Environmental Concentration (PEC) to Predicted No Effect Concentration (PNEC). It also obliges authorities to use the CHARM "hazard assessment" module as the primary tool for ranking. The Cefas Offshore Chemical Notification Scheme team conduct this work for both the UK and Netherlands.

Inorganic chemicals and organic Chemicals with functions for which the CHARM model has no algorithms are ranked using the Cefas OCNS hazard groups. A complete description of the OCNS PBT assessment process can be found in the Cefas protocols.

All products currently registered by Cefas for either the Netherlands or the UK are presented on the ranked lists. The lists use a banding system to rank organic chemicals of similar function according to PEC:PNEC 'Hazard Quotients' calculated using the CHARM model. The banding system is not applicable to the Netherlands.

The minimum data set of actual values and the parameters used by Cefas to calculate them will be disclosed to chemical suppliers on 'templates'. The supplier may then pass these on to operators to enable the calculation of site-specific risk assessments (RQs) for any chemicals they may want to use. Some chemicals are generated/used 'in situ' on offshore installations, e.g. Sodium Hypochlorite, and don't fall under the remit of any one supplier. Templates for such chemicals will be available as Adobe Acrobat file downloads.

Once classified, a product will typically remain on the List of Notified Chemicals for 3 years after which it becomes due for re-certification. However, products being used for a field trial or those containing substances recommended for substitution may have a shorter validity. When products are due for re-certification, a full HOCNF and SDS must be resubmitted.

The properties of substances on the OSPAR List of Substances/Preparations Used and Discharged Offshore, Which Pose Little Or No Risk to the Marine Environment (PLONOR) are sufficiently well known that OSPAR do not require them to be tested. This list is reviewed annually and the notification requirements for these chemicals are given in the PLONOR document.

Web links for OSPAR, DECC, SSM and Marine Scotland can be found on the OCNS Downloads and useful links.