Why this sector is different

Refineries, petrochemical plants and storage terminals handle large amounts of flammable and toxic material under pressure and heat. Day-to-day injuries look like those in other industries: slips, falls and hand injuries. The bigger danger is rare. A leak, a fire, an explosion or a toxic cloud can kill many people at once and reach beyond the fence.

MOM's 2025 national statistics count seven fatal and major injuries in petroleum and chemical products manufacturing. The same industry had 35 occupational disease cases, 33 of them noise-induced hearing loss. Low injury counts do not measure process safety. Track the near misses and the small leaks too.

The hazards to plan for

  • Loss of containment from leaking flanges, corroded pipes, overfilled tanks and failed seals.
  • Fire and explosion from flammable vapour meeting an ignition source.
  • Toxic gases such as hydrogen sulphide.
  • Confined spaces: tanks, columns, vessels and pits during turnarounds.
  • Hot work near live process units.
  • Energy release when breaking into lines or equipment that is not isolated.
  • Work at height on columns, pipe racks and scaffolds, often in the heat.
  • Noise from compressors, burners and venting.

What the rules require in Singapore

All the general WSH Act duties apply, including risk assessment under the WSH (Risk Management) Regulations. The process industry also has these sector rules.

  • Factory registration: refineries, petrochemical plants and bulk toxic or flammable liquid terminals with 5,000 cubic metres or more of storage are Group B factories. Major hazard installations are Group C (MOM).
  • WSH officer: required in factories that process petroleum or petroleum products (MOM).
  • Audits: petroleum and petrochemical factories need an external audit of their safety and health management system every 24 months. So do terminals storing 5,000 cubic metres or more of toxic or flammable liquids (MOM).
  • Training: manual workers in the oil and petrochemical industry need Apply WSH in Process Plant. Supervisors need Supervise WSH in Process Plant (MOM course list).
  • Flammable materials: the WSH (General Provisions) Regulations put them under a competent person's control and keep ignition sources apart. Firefighting equipment must be accessible and tested (WSH Council flammable materials guidelines).
  • Confined spaces need entry permits, gas tests and attendants under the WSH (Confined Spaces) Regulations 2009.
  • Process plants listed in the regulations need a fall prevention plan under the WSH (Work at Heights) Regulations 2013, and an on-site WBGT meter for heat (MOM).
Major hazard installations

Under the WSH (Major Hazard Installations) Regulations 2017, a site found to be an MHI must hold a Certificate of MHI Registration. A new MHI must submit its safety case to MOM's Major Hazards Department at least 6 months before it starts operating. An existing MHI renews its registration at least 6 months before expiry (MOM).

Process safety management

The WSH Council's process safety pages describe the aim simply. Design the plant well, run it safely, maintain it properly, and keep systems that watch and control the hazards. Technical, management and operational systems must work together. SS 651 sets out a safety and health management system for the chemical industry.

Measure it. The WSH Council's process safety performance indicators guidance splits indicators into two kinds. Leading indicators check controls before anything goes wrong, such as overdue hazard study actions or out-of-date safety data sheets. Lagging indicators count the leaks, fires and trips that already happened.

Order of controls

Start with inherent safety. Store less, use less hazardous materials, and run at lower pressure or temperature where the process allows. Design for containment with proper materials, relief systems and corrosion allowances.

Then add engineering layers: gas detection, emergency shutdown, fire and gas systems, bunds, and blast-rated buildings for occupied rooms. Next come procedures: operating limits, management of change, permits and isolation. Breathing apparatus, fire-resistant clothing and gas monitors are the last layer.

Controls that matter during maintenance

  • A permit-to-work for every hot work, confined space entry and line break.
  • Positive isolation with blinds or spades, not just closed valves, before opening equipment.
  • Gas testing before and during hot work, with a fire watch posted.
  • A management of change review before any change to plant, process or staffing.
  • Clear handover at shift change, written and spoken.
  • Contractor briefings on site hazards, alarms and muster points before turnarounds.
Treat small leaks as warnings

A weeping flange or a small vapour release is a free lesson. Log it, investigate it and fix the cause. Major accidents are often preceded by many minor ones.

Common mistakes

  • Using a low injury rate as proof that the plant is safe.
  • Leaving alarms in bypass long after the job that needed it.
  • Small changes, such as a new gasket type, made with no change review.
  • Too many permits issued by one person, so none are checked properly.
  • Contractors arriving for a turnaround without a site-specific briefing.
  • Rescuers entering a vessel without breathing apparatus.

Related topics on this site

  • Permit to work, Hot work and Confined spaces.
  • Fire and emergency, and Chemical safety.
  • Working at height and Scaffolding.
  • Contractor management and Risk assessment.
  • Heat stress, Noise and Incident investigation.

In other countries

  • Malaysia: Major hazard installations fall under the Occupational Safety and Health (Control of Industrial Major Accident Hazards) Regulations 1996, known as CIMAH. DOSH's 2023 guidance says the CIMAH report must reach DOSH 3 months before the activity starts. DOSH reads this as 3 months before hazardous substances arrive on site. The report is reviewed every 3 years, and sooner after a change that materially affects it.

Sources

  1. Workplace Safety and Health Report 2025: National Statistics, Ministry of Manpower.
  2. Workplace Safety and Health (Risk Management) Regulations, Singapore Statutes Online.
  3. Factory notification or registration requirements, Ministry of Manpower.
  4. Requirements for a safety and health management system, Ministry of Manpower.
  5. List of Workplace Safety and Health courses (updated 18 March 2025), Ministry of Manpower.
  6. MHI assessment and registration, Ministry of Manpower.
  7. Workplace Safety and Health (Major Hazard Installations) Regulations 2017, Singapore Statutes Online.
  8. About process safety, WSH Council.
  9. Process safety performance indicators, WSH Council.
  10. Workplace Safety and Health (Confined Spaces) Regulations 2009, Singapore Statutes Online.
  11. Workplace Safety and Health (Work at Heights) Regulations 2013, Singapore Statutes Online.
  12. Heat stress measures for outdoor work, Ministry of Manpower.
  13. WSH Guidelines on Flammable Materials, WSH Council.
  14. Guidance for Preparation and Updating of Report on Industrial Activity (2nd edition, 2023), DOSH Malaysia.

This is practical guidance, not legal advice. Laws and codes of practice change; always check the current official text and your site's own procedures.