Health and Safety Executive

OCE Use of drilling muds (shale shaker and mud Offshore pit areas) COSHH Control approach 2 essentials Engineering control

This information will help offshore What this sheet covers dutyholders (owners, operators and This sheet describes good practice for control of exposure to drilling contractors) to comply with the Control muds (liquids, mists and vapours) in shale shaker and mud pit areas. of Substances Hazardous to Health It includes mud handling, sampling and cleaning activities. It covers Regulations 2002 (COSHH), as amended, to the key points you need to follow to help reduce exposure to an protect workers’ health. acceptable level, as part of your COSHH assessment.

This sheet does not cover mud making. This guidance consolidates good control practice and reinforces existing knowledge with additional information.

It will help you carry out COSHH assessments, review existing assessments, deliver training and in supervising activities involving substances hazardous to health.

It is aimed at staff whose responsibilities include the management of substances hazardous to health on offshore installations (eg occupational health specialists, COSHH assessors, supervisors etc). It is also useful for trade union and employee safety representatives.

Hazard Following this guidance is not compulsory and you are free to take other action. But 3 Drilling muds contain a wide range of substances including base fluids (eg mineral oils/calcium chloride), weighting agents (eg barite), if you do follow this guidance, you will viscosifers (eg bentonite), surfactants (eg imidazolines) and biocides (eg normally be doing enough to comply with glutaraldehyde). the law. Health and safety inspectors seek to secure compliance with the law and may 3 Muds can also contain contaminants from formations (eg oil, condensate and H2S). refer to this guidance as illustrating good practice. 3 Hot muds will generate mists and vapours. 3 Health effects include dermatitis, respiratory irritation, narcosis and cancer. Also see essential information on the back of the sheet. 3 H2S is a very toxic gas, it can irritate the eyes, and throat and can cause unconsciousness and death (see OCE6). 3 Good practice benchmark values for total oil vapour is 50 mg/m3 and oil mist is 1 mg/m3 (Norwegian limits). 3 Individual substances should comply with their workplace exposure limits (WELs) if available, or other relevant exposure standard.

Access 3 Restrict access to authorised personnel. 3 Impose confined space entry procedures for entry into a mud pit. 3 Keep access doors closed. Equipment and procedures Substitution 3 Use water-based muds where possible: otherwise use low toxicity base oil.

Control equipment 3 Cover mud troughs, sand traps etc fully to minimise vapour release. 3 Provide enough fresh air to dilute and remove air contaminants, eg above 15 air changes per hour with a through draught. 3 Provide fixed alarms for hydrocarbons and H2S. Shaker room 3 As far as possible, enclose the shaker in an LEV enclosure. 3 Where open, fit canopy hoods with plastic strips to maximise enclosure. 3 The enclosure should have an inward air speed of at least 0.5 metres/ second through gaps, to prevent mist escaping. 3 When retrofitting LEV, install a full enclosure. Cabin 3 Provide a cabin in the shaker room to protect workers from hazardous substances and noise. 3 Filter inlet air: a pre-filter and HEPA filter – type H11 for respirable dust below 1 mg/m3, or type H12 or H13 for higher concentrations. 3 Maintain an over-pressure around 10 Pa to minimise air ingress. Fit a gauge to show this is working correctly and a filter failure alarm. 3 The cabin should have self-closing doors, flaps to relieve excess pressure, and a sticky dust mat.

Mud pit room 3 Cover mud pits and sampling hatches. 3 Only open hatch lids when sampling then close them. 3 Extraction of mud pits should have an inward air speed of at least 0.5 metres/second.

Sampling mud and cuttings 3 Ensure that samplers follow the rules for access to the areas. 3 Provide a tool to remove mud from the pit or cuttings from the screen. 3 Drain the cuttings – return the fluid to the system. 3 Provide closeable containers for transfer to the laboratory. All extraction 3 Fit an airflow indicator to show that extraction is working properly. 3 Discharge extracted air to a safe place.

Processing cuttings Employee checklist 3 Enclose the transfer of cuttings between the shaker and the cleaning unit. Is the equipment in good 3 Provide an enclosed and extracted cleaning unit. condition and working properly? Personal protective equipment (PPE) – see OCM3 3 Ensure that all items of PPE are compatible. Is the extraction working?

Is your respirator working Respiratory protective equipment (RPE) – see OCM4 properly? Check it every 3 RPE will be needed for cleaning (eg shaker screens) activities. time. 3 Provide CE-marked RPE for vapour with an assigned protection factor of at least 10 for cleaning and for emergencies. Look for signs of leaks, wear and damage before Other protective equipment every job. 3 Provide a ‘slicker suit’ and a visor for low-pressure cleaning. Look for signs of wear 3 Provide clean chemical-resistant gloves, eg nitrile, and new gloves and damage to when these are damaged. equipment.

Maintenance, examination and testing If you find any problem, get it fixed. Don’t just Checking and maintenance carry on working. 3 Check for signs of damage at the start of every shift. 3 At least once a week, check that airflow indicators work properly. Co-operate with health 3 Change inlet air HEPA filters as advised by the manufacturer. surveillance. 3 Check shale shaker seals and mountings and the enclosure integrity. Use, look after and store 3 Keep this information in your testing logbook. your PPE in accordance with instructions. Examination and testing 3 Extraction systems require statutory ‘thorough examination and testing’ Wash hands before (TExT). eating, drinking or using 3 Get a competent ventilation engineer to perform the TExT at least once the lavatory. every 14 months (see HSE publication HSG258). 3 Carry out all actions arising from the TExT. RPE 3 Examine and test RPE thoroughly at least monthly and infrequently used RPE at least three monthly. Replace worn parts.

Records 3 Keep records of all examinations and tests for at least five years. Exposure monitoring 3 Prove that you are using the right level and type of RPE – use monitoring records or carry out personal air monitoring

Cleaning and housekeeping

3 Clean the cabin once a week. Use a Class H vacuum cleaner or wet cleaning methods. 3 Provide a full set of PPE for low-pressure washing and shaker screen cleaning: RPE, slicker suit, gloves, boots, visor and goggles.

Caution: Do not use a brush or compressed air for cleaning. Never use compressed air to remove dust from clothing.

3 Label bags of dirty clothing to warn the laundry about the hazard. Other hazards n Noise

Waste n Musculoskeletal disorders –

3 Residues are ‘hazardous waste’. Label containers clearly – include a manual handling awkward UN number where appropriate. Store and dispose of waste safely. heavy items in restricted places Personal decontamination and skin care n Hydrogen sulphide (H S) 2

3 Provide warm water, mild skin cleansers, nailbrushes, and soft paper, n Substances harmful to the

fabric towels or hot air for drying. Avoid abrasive cleansers. marine environment 3 Instruct workers in how to clean their skin effectively. 3 Tell workers to wash hands before every break. Further information 3 Provide pre-work skin creams, which will make it easier to wash dirt Petroleum Industry Training from the skin, and after-work creams to replace skin oils. Service Non Water-based Drilling and Completion Fluids Caution: ‘Barrier creams’ or ‘liquid gloves’ do not provide a full barrier. Industry Recommended Practice IRP Vol.14 2002 Health surveillance 3 Conduct low-level health surveillance for dermatitis involving skin Drilling fluids and health risk checks by suitably trained responsible person. management: a guide for drilling personnel, managers and health Training and supervision professionals on the oil and gas 3 Provide supervision – ensure that safe work procedures are followed. industry OGP/IPIECA 2009 3 Tell workers, including maintenance workers, what the hazards and Respiratory protective risks are. equipment at work: A practical 3 Explain the early signs of dermatitis. guide HSG53 (Third edition) 3 Training includes toolbox talks on: HSE Books 2005 n how to use equipment properly; ISBN 978 0 7176 2904 6 n how to check that extraction is working properly; www.hse.gov.uk/pubns/books/ n how to use RPE and check that it is working; hsg53.htm n how to clean up spills correctly; and

n what to do if something goes wrong. Controlling airborne 3 Involve managers and supervisors in health and safety training. contaminants at work: A guide to local exhaust ventilation (LEV) Essential information HSG258 HSE Books 2008 OCE0 Advice for managers ISBN 978 0 7176 6298 2 OCM1 Confined spaces www.hse.gov.uk/pubns/books/ OCM2 Local exhaust ventilation (LEV) hsg258.htm OCM3 Personal protective equipment (PPE) Workplace exposure limits EH40 OCM4 Respiratory protective equipment (RPE) www.hse.gov.uk/coshh/table1.pdf OCM7 Health surveillance OCE16 Bulk sampling You can find the full Offshore OCE26 Drilling waste treatment COSHH essentials series at www.hse.gov.uk/coshh/index.htm

This guidance was developed by representatives from the UK offshore oil and gas industry and trade unions, with HSE.

© Crown copyright 2011 Published by the Health and Safety Executive 03/11