Chemicals – Drilling 

For information on the impact of Brexit on oil and gas environmental legislation, please refer to the pdf document downloadable from the Home Page.

Key Legislation:

For more detail on the Legislation relevant to this page, please use the following links:

Supporting Legislation:
  • The NSTA published a well consents guidance covering the consent requirements for:
    • Well installation;
    • Well tests or extended well tests; and
    • Well abandonment and suspension.

    The guidance details when applications, consents and notifications to NSTA are required and the information that NSTA takes into consideration when determination such applications.

Consent Needed (also see OBM and SBM Use and WBM Use and Discharge for further non-chemical consent requirements):

There is a requirement for the operator to obtain a permit to use and discharge drilling chemicals. This permit must be in place before commencement of operations.

For discharges of excess cement and other surplus material at end of operations – see the Performance Standards tab.

Marine Licensing Exempt Activities – A list of exemptions to marine licensing has been published and it details activities exempt from marine licensing and which exemptions require the MMO to be notified and which exemptions require MMO approval. This includes ‘cables and pipelines – authorised emergency repair and inspection’ and ‘deposit of marine chemical and marine oil treatment substances’.

What to Include to Permit Authorisation:

An application for the grant of a permit from the Department for Energy Security and Net Zero under regulation 4 is made via an electronic drilling operations application. It shall contain:

  • A description of the offshore source on or from which the offshore chemical is to be used or discharged, and the location of the offshore source in the relevant area
  • A description of the proposed technology and other techniques for preventing or, where this is not possible, reducing the use or discharge of the offshore chemical from the offshore source
  • A description of the measures planned to monitor the use or discharge of the offshore chemical
  • An assessment of the risk of damage to the environment from the use and discharge of the offshore chemicals proposed.

The regulations allow for the acquisition of further information if that submitted is deemed insufficient or incorrect and for the gathering of evidence to verify any statements made.

Note: The drilling operations application will consist of two elements: the Master Application Template (MAT) and the Subsidiary Application Template (SAT). Completion of the MAT provides access to various SATs:

In addition, as part of ongoing reviews of oil spill contingency arrangements in light of the Macondo well incident, drilling operation applications for exploration, appraisal or development wells must:

  • Confirm that the operation is covered by an approved OPEP or OPEP application
  • If hydrocarbons are expected, include the maximum expected volumes
  • Include a section dealing with accidental events, summarising the worst-case scenarios assessed and modelled in the OPEP and the measures in place to prevent and control the release
  • Include or reference any relevant environmental impact assessment studies

Additional changes may be required in the future, when the Department for Energy Security and Net Zero has reviewed outstanding reports relating to the Macondo incident.

How to Apply:

Applications should be made using the following forms: Wells and sidetracks (including new drilling from platforms) – drilling operations application. Workovers, if part of the drilling programme (outside the platform 500m safety zone) – drilling operations application. Alternatively the well intervention operations application can be used for all workovers and well intervention programmes – see Workover.

Who to Apply to:

PETS applications must be submitted electronically to the Department for Energy Security and Net Zero via the UK Oil Portal. Operators will need to be registered with the Department for Energy Security and Net Zero for access to the Portal.  To set up a UK Oil Portal Account, contact the Department for Energy Security and Net Zero OED Environmental Management Team at  If you have any problems with PETS submission, contact the Department for Energy Security and Net Zero OED EMT by email at

When to Apply:

PETS (term permits) applications must be made at least 28 days before drilling commences. However, if also seeking a direction that an ES is not required, additional time should be allowed for. Well intervention operations applications must be made at least 28 days before workover or completion. Well intervention operations applications may be for annual or term permits (see Workover).

Requirements of the Regulations:

Operators will need to assess the risks to the environment, which might arise from their particular chemicals use and discharge. For some chemicals, e.g. those on the OSPAR PLONOR list, assessment will be straightforward. Others will require a formal process of risk assessment, such as can be done using CHARM software. In this process, the predicted environmental concentration (PEC), determined from a knowledge of individual substance or product chemistry and the conditions of use, is compared with the Predicted No-effect Concentration (PNEC) determined from toxicity tests conducted to agreed protocols. This allows more informed assessments of risk to local sensitivities to be made in particular use and/or discharge scenarios. The use of the CHARM model is compulsory for calculating the Hazard Quotient (HQ) but other risk assessment models may be used to calculate the Risk Quotient (RQ) provided comparability with CHARM can be demonstrated.


Pipe Dopes containing Lead: OSPAR has now published its overview assessment of the implementation of OSPAR Recommendation 2005/2 on environmental goals for the discharge by the offshore industry of chemicals that are, or contain added substances, listed in the OSPAR List of Chemicals for Priority Action. This refers to the treatment of pipe dopes containing lead. The discharge of pipe dopes containing lead is now prohibited. All future PETS applications to use pipe dopes containing lead should only relate to activities where there is no planned or anticipated “discharge” of the dope, and should accordingly be entered in the application and the EEMS return as Zero Discharge. Text should also be included in chemical risk assessment SAT and/or EIA SAT of the application to confirm the measures that will be taken to justify the zero discharge estimate (detailing how it is being used to ensure zero discharge). Discharges of these pipe dopes are now prohibited, and the Department will be refusing to accept applications that include a proposed discharge of pipe dopes containing lead.Alternative pipe dopes that do not contain lead can continue to be used for applications where there is an anticipated discharge, and should continue to be assessed and entered in the application and the EEMS return using the default 10% discharge estimate.
Controls Placed on the Type and Volume of Drilling Chemicals Discharged:

Conditions of an approved permit will indicate the types and volumes of chemicals that may be discharged into the environment. These conditions must not be exceeded.

Well Clean-up Fluids: See Well Clean-up
Well Abandonment: See Well Abandonment
UK National Plan for the phase-out of substances identified as candidates for substitution – in line with OSPAR Recommendation 2006/3:(The full text of the current UK National Plan for phase out can be found on the CEFAS website)

OSPAR Recommendation 2006/3 requires that as soon as is practicable and no later than 1 January 2017, Contracting Parties to OSPAR should have phased out the discharge of offshore chemicals that are, or which contain substances, identified as candidates for substitution except for those chemicals where despite considerable efforts, it can be demonstrated that this is not feasible due to technical or safety reasons. Demonstration of those reasons should include a description of those efforts. Having considered the requirements of OSPAR Recommendation 2006/3, the UK has decided to base its National Plan for the prioritisation of phase-out on the following criteria:

  • Perceived difficulty of phase out
  • Securing the replacement of candidates for substitution in preference to eliminating operational discharges to the marine environment
  • Prioritisation based on the persistence, bioaccumulation and toxicological properties of the chemical

The UK National Plan also incorporates justification of continued use and/or discharge as an additional element: for those substances where replacement and/or eliminating discharges to the marine environment is not currently feasible, offshore operators or their chemical suppliers will annually be required to:

  • Confirm the efforts made to phase out the use and/or discharge of the candidates for substitution
  • Confirm the nature and timing of planned research and development studies or trials to supplement those efforts conform whether any measures have been taken to reduce the use and/or discharge of the candidate for substitution
  • Confirm the technical and/or safety issues that make it necessary to continue use and/or discharge of the candidate for substitution.

UK National Plan level criteria and interim target dates are (See the full text of the UK National Plan (PDF  document) from the CEFAS website for definitions of persistence, bioaccumulating and toxicity):

  • Level 1 (highest priority)
    • Organic substances that are highly persistent, bioaccumulating and toxic
    • Chemicals to be replaced, or discharges to the marine environment to be eliminated or continued use and/or discharge to be formally justified by end December 2010.
  • Level 2
    • Moderately persistent, bioaccumulating and toxic, or
    • Highly persistent and bioaccumulating, or
    • Highly persistent and toxic chemicals
    • To be replaced, or discharges to the marine environment eliminated, or continued use and/or discharge to be formally justified by end December 2012.
  • Level 3
    • Moderately persistent and bioaccumulating, or
    • Moderately persistent and toxic, or
    • Bioaccumulating and toxic chemicals
    • To be replaced, or discharges to the marine environment eliminated and/or discharge formally justified by end December 2014.
  • Level 4 (lowest priority)
    • Highly persistent organic substances, or
    • Inorganic substances with toxicity <1mg/l
    • Chemicals to be replaced, or discharges to the marine environment eliminated, or continued use and/or discharge to be formally justified by the end of December 2016.

EC Regulation 1907/2006 (REACH):REACH deals with the Registration, Evaluation, Authorisation and Restriction of Chemical substances. The aim of REACH is to improve the protection of human health and the environment through the better and earlier identification of the intrinsic properties of chemical substances. At the same time, innovative capability and competitiveness of the EU chemicals industry should be enhanced. The benefits of the REACH system will come gradually as more and more substances are phased into REACH.

The HSE is the UK Competent Authority for REACH and is working closely with Defra plus other Government Departments and Agencies on the policy/enforcement aspects. HSE enforces maritime Health and Safety Regulations which apply to offshore installations.

To ensure a consistent regime, the offshore enforcement of REACH will be carried out by those who are familiar with enforcement requirements in similar circumstances to that required by REACH. Therefore, HSE and the Department for Energy Security and Net Zero will enforce offshore the aspects of REACH relating to health/safety and environmental protection, using their respective onshore administrative procedures and offshore inspectors to check compliance with the relevant provisions. In this regard, the Department for Energy Security and Net Zero sits on the REACH Enforcement Liaison Group (established by the HSE) to ensure that a proportionate and consistent method of enforcement is adopted.

From an offshore environmental protection perspective, the OSPAR HMCS and REACH requirements will run in parallel, with the HMCS approach to controlling offshore chemicals being appropriately harmonised with the provisions of the EU Regulation. Accordingly, the UK REACH Enforcement Regulations contain certain provisions from, and makes references to, the OCR, so effectively OCR (and hence the HMCS) will be the mechanism for supporting the application of the environmental protection elements of REACH to offshore installations. It should, however, be noted that the Department for Energy Security and Net Zero’s regulatory regime for offshore chemicals does not extend to Scottish controlled waters and therefore, in so far as this area is concerned, REACH will be enforced by an authorised body (i.e. SEPA) on behalf of the Scottish Executive. REACH provisions will be phased-in over 11 years.

Appendix 1 of the Department for Energy Security and Net Zero (then DECC) Guidance Notes on Reach (Word document) addresses Specific REACH issues pertaining to the offshore sector.A Timetable of REACH Implementation (Word document) is available on the Department for Energy Security and Net Zero Website.

Chemicals: All chemical use/discharge must be monitored and recorded. Components of oil based mud systems must be listed individually with their appropriate use and discharge (see the Reporting Requirements tab).
Routine Monitoring: Periodic monitoring of the area around installations may be requested to confirm impact hypotheses and to check that the general health of the marine environment in the vicinity of installations remains acceptable. The operator will carry out the monitoring and bear any costs involved.
Check Monitoring (Inspections): The Regulations state – “Government will, as circumstances dictate, conduct check monitoring. It will seek to confirm that routine monitoring is generating accurate returns. The costs of this monitoring will be recovered under the scheme”. Where an inspector considers that any activity in relation to the use or discharge of an offshore chemical involves a serious and imminent risk of pollution, he may give such directions in relation to that activity (including a direction requiring the cessation of that activity), as he considers necessary to avoid or minimise the risk of pollution in question.
What to Report:

Chemical Use and Discharge

Reports should be made on all drilling and well chemicals, as required by the Department for Energy Security and Net Zero, electronically via the EEMS website. Reports are made on the drilling chemicals and fluids with spreadsheets also available for download on the EEMS website. As well as being used by the Department for Energy Security and Net Zero to check actual use and discharge of chemicals against the term permit, they will also be used towards compilation of the OSPAR returns, which Contracting Parties are obliged to make. For certain problematic substances, such as those identified for substitution, the Department may require more frequent reporting. A condition in the permit will make this clear if necessary.

Annual Progress Reports on Substitution Chemicals

Previously progress reports on substitution chemicals have only been requested for production chemicals (Production operation permit). This reporting requirement is now extended to term permits. A reporting template can be downloaded here (documents can be found under the reporting requirements section Offshore Chemicals Regulations 2002 (as amended)). Reporting includes summary of chemicals replaced, summary of chemicals still to be replaced and justification for continued use and/or discharge. This guidance document explains the completion of reporting spreadsheets. Some minor modifications have been made to the Annual Reporting spreadsheets and the Technical Justification Report (TJR) spreadsheet since the 2014 version.

Who to Report to:

Chemical Use and Discharge  Reports need to be made electronically on the EEMS website after each well. the Department for Energy Security and Net Zero will use EEMS reports to cross check against permit conditions to ensure compliance.

Annual Progress Reports on Substitution Chemicals

Reports need to be submitted to the Department for Energy Security and Net Zero Environmental Management Team by email to

When to Report: Chemical Use and Discharge  EEMS reports to be submitted 28 days after permit expiry date. Annual progress reports are required to be submitted on or before 28 February of each calendar year.
Non Compliance: Any non-compliance with permit conditions under the Offshore Chemicals Regulations (OCR) 2002 should be reported to OPRED via the Integrated Reporting Service (IRS) on the UK Energy Portal. If the IRS is unavailable, an OCR non-compliance notification form should be sent to OPRED. Examples of non-compliance may include, but are not limited to: identified overuse of chemicals or use and/or discharge of chemicals not included on the permit. In addition the form may be used to notify the Department for Energy Security and Net Zero of any other applicable notifications specifically as required by the chemical permit conditions as appropriate. Variations to chemical permits should be made before exceeding permit limits. Emergency approval of chemical use and/or discharge can be obtained out of normal office hours by contacting the Department for Energy Security and Net Zero Duty Officer – ask to be connected to the On-Call Response Office (Offshore Environmental Inspectorate). Guidance on emergency approval can be found in the Guidance Notes of the Legislation tab. If a variation is not in place before the unpermitted use or discharge occurs, a non-compliance notification form should be submitted. It is an offence not to submit a non-compliance report if required.
Chemical Spill: Any accidental spill of chemicals must be reported to OPRED using a PON1 (see Chemical Spills for additional details).
Inspections: At any reasonable time (or in a situation which in his opinion may give rise to a risk of significant pollution to the environment as a result of the use or discharge from an offshore source of an offshore chemical, at any time) the inspector may board any offshore installation to undertake inspections and investigations. The Department for Energy Security and Net Zero (then DECC) Environmental Inspectorate Enforcement Policy (PDF document) sets out the general principles that Inspectors shall follow in relation to enforcement, including prosecution.
Enforcement and Prohibition Notices:

The Department for Energy Security and Net Zero, if of the opinion that the OCR 2002 Regulations have been contravened, may issue an enforcement notice. This will specify:

  • The matters that constitute or are likely to constitute a contravention
  • The steps required to rectify the matter
  • The time period within which these steps must be undertaken

If an enforcement notice is not addressed, the Department for Energy Security and Net Zero may take action itself and recover reasonable costs back from the operator. If the Department for Energy Security and Net Zero is of the opinion that the operation of an offshore installation involves an imminent risk of serious pollution as a consequence of any discharge of chemical, the Department for Energy Security and Net Zero may serve a prohibition notice. This will specify the pollution risk, the steps required to remove it and the time period, and may withdraw a permit wholly or in part until the prohibition notice is withdrawn.

False or Misleading Information: The Department for Energy Security and Net Zero may by notice revoke a permit granted where they are of the opinion that the application for the permit in question contained any information or statement which was false or misleading in a material particular or where the operator in question has been guilty of a breach of any condition attached to the permit.

A person is guilty of an offence if he:

  •  Uses or discharges any offshore chemical in the relevant area without a permit
  •  Uses or discharges any offshore chemical in breach of the terms of any condition attached to any permit
  • Is seen by an inspector to use or discharge of an offshore chemical that involves a serious and imminent risk of pollution
  • Fails to supply any information required to be supplied by virtue of the terms of any permit granted under these Regulations
  • Knowingly or recklessly makes a statement which he knows to be false or misleading in a material particular where such a statement:
    • Is made in connection with or for the purposes of, any application for a permit, the renewal of a permit or the variation of a permit, or
    • Is made for the purposes of satisfying any requirement under these Regulations for the supply of information to the Secretary of State or an inspector appointed pursuant to regulation 16
  • Willfully obstructs an inspector, or
  • Without reasonable excuse fails to comply with an obligation imposed in pursuance of the regulations or prevents another person from complying with such a requirement.
Permit Duration: Permits for drilling chemicals will normally be issued for a specified period and are “Term Permits”.
Renewal of Permit: This is not applicable as permits are issued for a specified well. the Department for Energy Security and Net Zero must be notified of any drilling schedule changes. If the permit expiry date is likely to be exceeded, a variation should be submitted in order to extend the permit, at least 2 weeks before the due date. Otherwise a new application (28 days) will be required.
Update, Variation or New Permit: Applications need to be made to the Department for Energy Security and Net Zerofor a variation in the terms and conditions of a permit if there is any increase in the use and discharge of chemicals or changes in the chemicals used. All applications need to be considered by the Department for Energy Security and Net Zero and MS (CEFAS in England and Wales).Update – change made after the application but before approval has been given.Variation – change made after approval has been given.Application for a variation or update should be made by clearly amending the previously submitted permit application .  All PETS submissions must be linked to the relevant WONS well file for the drilling consent application (PON4). Where a drilling programme is amended, the need to submit either a permit variation or new permit will depend on whether the change to work programme would be classed as a re-drill (i.e. if a new WONS well file would be generated). If a new WONS well file is needed, a new permit will also be required. Otherwise, a variation of the existing permit can be submitted.If submitting a variation, all sections should be completed describing any changes in drilling and chemical usage relating to the new works. Variations will be dealt with by the Department for Energy Security and Net Zero as quickly as possible, but 28 days should be allowed for the assessment of any significant changes.Note: a variation cannot be submitted once a Term Permit has expired. A new application must be submitted.
Drilling Outside Expected Spud Date: Changes in spud dates – the Department for Energy Security and Net Zero doesn’t want to be prescriptive and ishappy to see a drilling window based on risk. Normally the Department for Energy Security and Net Zero will limit the permit duration to one month either side of the drilling window – anything beyond this will need to be justified. Where the Department for Energy Security and Net Zero asks for spud date, i.e. in the MAT of the permit, this should be given and the narrative section used to explain where and why there is built-in flexibility. For example if the expected spud date is the 15th March and a total drilling period of 60 days then the 15th of March should still be quoted in the MAT but environmental sensitivities and possible impacts should cover the period from February to June. If drilling occurs within this window, the only notification to the Department for Energy Security and Net Zero will be the new spud date that should be advised through WONS. If drilling is due to start before, or continue after, the window notified in the permit, the sensitivities addressed in the application must be examined to assess whether there is any significant adverse change. The conclusion should be advised to the Department for Energy Security and Net Zero’s  Environmental Manager who handled the original permit by email, in addition to advising WONS. It should be noted that extra time must be allowed as the Department for Energy Security and Net Zero may need to go back to JNCC in cases where drilling will occur outside the original window.
Field Trials for New Chemicals: It is likely that field trials involving the use and discharge of new chemicals can be encompassed through a request for a variation to an existing permit since a field trial will have been planned in advance. If there is any doubt about how this should be handled, then the operator and the chemical company are strongly advised to discuss the proposed field trial with the Department for Energy Security and Net Zero and MS or CEFAS (as appropriate) first.
Surrendering a Permit: An operator may by notice surrender a permit granted to him.
Copper Anti-fouling Systems under Biocidal Products Directive:

A new legal requirement came into force under the EU Biocidal Products Directive 98/8/EC, prohibiting the supply and use of copper as a biocide when used in liquid-cooling and processing systems.
Copper is used offshore in a number of systems e.g. sea water lift, fire water systems, injection systems, ballast systems andengine cooling HVAC cooling.
Although not an exhaustive list, oil and gas operators should check all systems/vessels/installations using copper anti-fouling systems, or when used as a biocide in liquid-cooling and processing systems.

Further details are available from the Anti-Fouling Systems page.

DECC Environmental Alert (001/2014)- PON1 Reporting:

Issued by DECC (now Department for Energy Security and Net Zero) on 31 March 2014, this environmental alert (PDF document) highlights failures by a number of operators to comply with PON1 reporting requirements. Operators are reminded that in accordance with current reporting requirements PON1s must be reported within 6 hours to:

  • Aberdeen Maritime Rescue Coordination Centre (MRCC) in addition to immediate telephone notification to the nearest MRCC Coastguard Station.
  • The Department for Energy Security and Net Zero; additional telephone notification is required to the Department for specific scenarios as detailed within the PON1 reporting guidance.
  • Joint Nature Conservation Committee (JNCC) and any relevant Statutory Nature Conservation Body (SNCB) in accordance with installation oil pollution emergency plan arrangements.
Environmental Alert Notices The Department for Energy Security and Net Zero regularly issues environmental alert notices in order to raise awareness of any environmental issues on the United Kingdom Continental Shelf (UKCS) so companies can respond appropriately. They are issued directly to Oil and Gas operators and published here.
Oil and Gas Authority (OGA) exploration strategy The OGA has published an exploration strategy which outlines the key strategies which will be used to underpin maximum economic recovery of the UKCS.
OPRED’s announcement regarding inactive OPRED applications OPRED has announced that it has officially revoked the PON15 application (PON15b, PON15c, PON15d and PON15f) application types from the UK Energy Portal.
Reporting Mud Components:

Reporting of use and discharge must be undertaken on a component basis of the whole mud. Where a mud is recycled, the Department for Energy Security and Net Zero has agreed that for reporting purposes, the assumption can be made that the recycled mud being used for a base is a mixture of the predominant base oil and barites and can be reported as such. Where additional additives are added to the recycled mud, these will need to be reported separately.

Update on OGA approach to licence amendments (July 2021) The OGA has announced that they will now make licence amendments in the same way as was done pre-COVID.
Use and Discharge of Jacking Greases: Use and discharge of jacking greases for jack-up rigs must now be included in each drilling operations application or well intervention operations application as appropriate.
Use and discharge of lead within UKCS: In September 2014, DECC (now Department for Energy Security and Net Zero) issued a letter to all Operators / Owners of Installations and Mobile Drilling Units about the continued supply and use of lead by operators within UKCS, reminding them of their responsibility to ensure that Government commitments are adhered to in order to meet OSPAR objectives and the Directive on Environmental Quality Standards (2008/105/EC) requirements.