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100+ Free NEBOSH PSM Practice Questions

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Key Facts: NEBOSH PSM Exam

40 questions

PSM1 Online MCQ Exam (10 scenario-linked)

NEBOSH PSM specification

90 minutes

Exam Duration

NEBOSH PSM specification

60%

Pass Mark (24 of 40)

NEBOSH PSM specification

Monthly

Remotely Invigilated Exam Sittings

NEBOSH

48 hours

Recommended Study (28 taught + 20 private)

NEBOSH Learning Partner guide

SCQF Level 7

Credit Rating (comparable to RQF Level 4)

Qualifications Scotland

No expiry

Certificate Validity

NEBOSH

The NEBOSH HSE Certificate in Process Safety Management suits supervisors, engineers, and HSE professionals on major hazard plants. Unit PSM1 is a 90-minute, remotely invigilated online exam of 40 multiple-choice questions (10 of them extended scenario questions) with a 60% pass mark (24/40), offered monthly. The syllabus has four elements: process safety leadership (leading/lagging indicators per HSG254, management of change, lessons from Buncefield, Texas City, Flixborough, and Piper Alpha); management of process risk (COMAH duties, HAZOP, LOPA, bow-ties, permit-to-work, safe shift handover, contractor management, asset integrity); process safety hazard control (safe operating limits, safety instrumented systems and SIL, utilities, static electricity, DSEAR zoning, runaway reactions, tank and LPG storage, road tanker transfer); and fire and explosion protection (jet/pool fires, BLEVE, vapour cloud and dust explosions, inerting, relief and suppression systems, COMAH emergency planning). NEBOSH recommends about 28 taught hours plus 20 hours of private study, and results issue within 15 working days.

Sample NEBOSH PSM Practice Questions

Try these sample questions to test your NEBOSH PSM exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 100+ question experience with AI tutoring.

1Which statement BEST describes how process safety differs from personal (occupational) safety?
A.Process safety addresses high-frequency, low-consequence events such as slips, trips, and manual handling injuries
B.Process safety focuses on preventing low-frequency, high-consequence events such as major fires, explosions, and toxic releases caused by loss of containment
C.Process safety is concerned only with long-term occupational health exposures such as noise and dust
D.Process safety relies on individual worker behaviour rather than the integrity of engineered systems
Explanation: Process safety is concerned with preventing catastrophic but rare events - loss of containment of hazardous substances or energy leading to major fires, explosions, or toxic releases. It depends on plant design, asset integrity, and management systems rather than individual behaviour alone.
2Following the BP Texas City refinery explosion in March 2005, the Baker Panel identified a fundamental flaw in how the company measured safety performance. What was that flaw?
A.The refinery measured too many leading indicators and ignored injury statistics
B.The refinery benchmarked its performance only against other BP sites rather than the wider industry
C.The refinery had no system at all for recording incidents or near misses
D.The refinery relied on low personal injury rates as evidence that process safety risks were under control
Explanation: The Baker Panel found that BP mistakenly interpreted improving personal injury rates (such as lost-time injury frequency) as an indication of acceptable process safety performance, masking deteriorating asset integrity and rising process risk at Texas City.
3At the Buncefield oil storage depot in December 2005, a tank overfilled with petrol and the resulting vapour cloud exploded. What combination of failures allowed the overfill to occur?
A.The automatic tank gauge stuck so the level appeared static, and the independent high-level switch was inoperable because it had been left in a non-working state after testing
B.The tank inlet valve was opened manually by an operator who ignored a high-level alarm that was working correctly
C.Lightning struck the tank vent during a thunderstorm while the tank was being filled at the maximum permitted rate
D.A corroded tank shell split at the weld seam, releasing petrol below the maximum fill level
Explanation: Tank 912's automatic tank gauging servo gauge stuck (flat-lined) so operators saw no rising level, and the independent high-level switch failed to operate because a padlock needed to retain its test lever had not been fitted - both layers of protection failed and petrol overflowed from the tank roof vents.
4According to HSE guidance HSG254 on developing process safety indicators, which of the following is an example of a LEADING indicator?
A.The number of loss of primary containment incidents in the last 12 months
B.The total cost of property damage from process incidents
C.The percentage of safety-critical plant maintenance tasks completed on schedule
D.The number of activations of emergency shutdown systems following real demands
Explanation: Leading indicators measure inputs - whether the risk control systems are operating as intended. The proportion of safety-critical maintenance completed to schedule shows whether the maintenance risk control system is being delivered, before any failure occurs. HSG254 recommends pairing leading and lagging indicators for dual assurance.
5The Process Safety Leadership Group (PSLG) was established after the Buncefield explosion. Its principles of process safety leadership state that direction and accountability for process safety must come from which level of an organisation?
A.The site safety committee, because it includes worker representatives
B.The board of directors, with a named director given specific process safety accountability
C.Front-line supervisors, because they are closest to day-to-day operations
D.External consultants, to guarantee independence from commercial pressure
Explanation: PSLG principles require board-level leadership: process safety should be a core value with clear board accountability, board-level visibility of process safety performance indicators, and a named director responsible for process safety.
6At Flixborough in 1974, a temporary 20-inch bypass pipe connecting two cyclohexane reactors failed, causing a vapour cloud explosion that killed 28 people. What key process safety failing did the disaster expose?
A.The plant modification was installed without proper engineering design, review, or testing - there was no effective management of change
B.Operators deliberately overrode a high-pressure trip to maintain production rates
C.The site had no permit-to-work system for hot work near the reactors
D.Cyclohexane had been incorrectly classified as a non-flammable substance
Explanation: After reactor 5 was removed due to a crack, a dog-leg bypass was improvised - sketched in chalk on the workshop floor and supported on scaffolding - without design calculations or review by a qualified mechanical engineer. Flixborough is the defining case for rigorous management of change for plant modifications.
7Which of the following changes would NOT normally need to go through a formal management of change (MOC) procedure?
A.Increasing the operating temperature of a reactor by 15 degrees C to improve yield
B.Connecting a temporary hose to bypass a fouled heat exchanger for one shift
C.Replacing a failed pump with an identical pump of the same specification from the same manufacturer (replacement in kind)
D.Reducing the number of control room operators per shift from three to two
Explanation: A true replacement in kind - identical specification, materials, and duty - does not change the plant's design basis, so it is normally handled through maintenance procedures rather than MOC. All genuine changes to process conditions, plant configuration, or organisation require MOC review.
8A maintenance team proposes a temporary modification to keep a unit running until the next planned shutdown. What control should a management of change system apply specifically because the modification is TEMPORARY?
A.The modification can be approved verbally by the shift supervisor since it will be removed later
B.The risk assessment can be simplified because the exposure period is short
C.No as-built drawings need to be updated for temporary equipment
D.A defined expiry date must be set, with the modification removed or formally re-approved when that time limit is reached
Explanation: Temporary modifications require the same engineering rigour as permanent ones, plus a time limit. The MOC system must track the expiry date and force removal or formal re-authorisation - temporary changes that quietly become permanent are a recognised cause of major accidents.
9An investigation into a loss of containment finds that a corroded pipe failed. The investigation team wants to identify the ROOT causes. Which finding is a root cause rather than an immediate cause?
A.The pipe wall had thinned below the minimum allowable thickness
B.The inspection programme had been progressively cut back for budget reasons without any assessment of the risk impact
C.The pipe was carrying a corrosive process fluid
D.The failure occurred at a dead-leg where fluid stagnated
Explanation: Root causes are the underlying management system failures that allow immediate causes to exist. Cutting inspection without risk assessment is an organisational decision-making failure - correcting it prevents whole classes of similar failures, not just this pipe.
10Why is worker engagement particularly valuable to the control of process safety risks?
A.Front-line workers often detect early warning signs - such as passing valves, unusual noises, or procedural workarounds - that management systems alone would miss
B.Engaging workers removes the employer's legal responsibility for process safety
C.Worker engagement allows the site to reduce the frequency of formal plant inspections
D.Engagement is mainly useful for negotiating shift patterns and pay rather than safety
Explanation: Operators and maintenance technicians interact with the plant daily and frequently notice degraded conditions, alarm problems, and procedure-versus-practice gaps before they appear in formal monitoring. Effective engagement captures this intelligence and builds ownership of process safety controls.

About the NEBOSH PSM Exam

The NEBOSH HSE Certificate in Process Safety Management is a joint qualification from NEBOSH and Great Britain's Health and Safety Executive for people working in process industries such as oil and gas, chemicals, plastics, and pharmaceuticals. It covers process safety leadership, management of process risk, process safety hazard control, and fire and explosion protection, and is the recognised successor to the withdrawn NEBOSH International Technical Certificate in Oil and Gas Operational Safety (IOG). The single unit PSM1 is assessed by a 90-minute online multiple-choice exam of 40 questions, including 10 extended scenario questions, with a 60% pass mark. The exam is remotely invigilated and offered monthly, and the certificate does not expire.

Questions

40 scored questions

Time Limit

90 minutes

Passing Score

60% (24 of 40 marks)

Exam Fee

Typically GBP 400-700 for course plus exam through a NEBOSH Learning Partner; exam-only registration around GBP 164 (NEBOSH, developed in collaboration with the GB Health and Safety Executive (HSE))

NEBOSH PSM Exam Content Outline

15%

Process Safety Leadership

How process safety differs from personal safety; board-level leadership and the PSLG principles formed after Buncefield; leading and lagging performance indicators (HSG254, API RP 754 tiers); organisational learning from Buncefield, Texas City, Flixborough, Piper Alpha, Bhopal, and Seveso; management of change including temporary modifications; worker engagement; and competence management systems for safety-critical roles

16%

Risk Management Techniques

COMAH 2015 lower-tier and upper-tier duties (MAPP, safety report, the HSE/EA Competent Authority); HAZID at concept stage versus HAZOP guide-word deviation studies on P&IDs; LOPA with independent protection layer rules; bow-tie barrier diagrams; quantified risk assessment for individual and societal risk; the ALARP gross-disproportion test; inherent safety (intensification, substitution, attenuation, simplification); and the CCPS Risk Based Process Safety pillars

16%

Asset Integrity & Safe Systems of Work

Design, technical, and operating integrity through the asset life cycle; risk-based inspection and NDT (ultrasonic thickness, dye penetrant, radiography); corrosion under insulation; breakdown, preventive, and condition-based maintenance; performance standards for safety-critical elements (functionality, availability, reliability, survivability); permit-to-work essentials including hot work, cross-referencing, and hand-back; HSG253 positive isolation for vessel entry; confined space gas testing order; Buncefield-informed shift handover practice; and the plan-choose-control-monitor-review contractor cycle

18%

Process Hazard Control

Safe operating envelope and operating procedures; elevated risk of start-up, shutdown, and transient operations (Texas City); alarm management and alarm floods per EEMUA 191; safety instrumented systems under IEC 61511 - sensor, logic solver, final element, SIL 1-4 PFD bands, proof testing, and independence from the BPCS; utility hazards including nitrogen asphyxiation, steam water hammer, and loss of cooling; electrostatic controls (bonding, earthing, 1 m/s fill velocity); and DSEAR/ATEX zones 0, 1, 2 with equipment categories

17%

Dangerous Substances: Reactions, Storage & Transport

Exothermic runaway mechanisms (heat generation versus removal, Arrhenius doubling per 10 degrees C); semi-batch dosing as a basis of safety; DSC and adiabatic calorimetry screening; DIERS two-phase relief sizing; bund capacity (110% of the largest tank); fixed-roof versus floating-roof tanks and rim seal fires; PSLG independent automatic overfill protection; tank vacuum collapse; pressurised versus refrigerated LPG storage and BLEVE prevention; CLP flammable liquid flash point classes; drum storage segregation; and road tanker earthing, bottom loading, vapour return, and Emergency Action Codes

18%

Fire & Explosion Protection and Emergency Response

Fire triangle, LEL/UEL flammable range, flash point versus auto-ignition temperature; jet fires, pool fires, flash fires, fireballs, and BLEVE; vapour cloud explosion overpressure driven by congestion and confinement; dust explosion pentagon, secondary explosions, and Kst/St classes; flame arresters, nitrogen inerting below the limiting oxygen concentration, explosion venting and suppression; intumescent passive fire protection and foam/water active systems; catalytic versus infrared gas detection; and COMAH on-site/off-site emergency plans tested at least every three years

How to Pass the NEBOSH PSM Exam

What You Need to Know

  • Passing score: 60% (24 of 40 marks)
  • Exam length: 40 questions
  • Time limit: 90 minutes
  • Exam fee: Typically GBP 400-700 for course plus exam through a NEBOSH Learning Partner; exam-only registration around GBP 164

Keys to Passing

  • Complete 500+ practice questions
  • Score 80%+ consistently before scheduling
  • Focus on highest-weighted sections
  • Use our AI tutor for tough concepts

NEBOSH PSM Study Tips from Top Performers

1Learn the case studies as cause-and-lesson pairs: Buncefield (stuck gauge and inoperable high-level switch leading to overfill, prompting PSLG independent overfill protection), Texas City (start-up overfill, mis-ranged level transmitter, reliance on personal injury rates), Flixborough (unengineered temporary bypass - management of change), and Piper Alpha (permit cross-referencing and shift handover)
2Memorise the hard numbers: 60% pass mark (24/40), bund capacity 110% of the largest tank, fill velocity limited to about 1 m/s until the dip pipe is submerged, SIL 2 PFD between 0.01 and 0.001, methane flammable range 5-15%, CLP flammable liquid flash point up to 60 degrees C, and COMAH emergency plans tested at least every 3 years
3Be able to generate HAZOP deviations by pairing guide words (NO, MORE, LESS, REVERSE, AS WELL AS, PART OF, OTHER THAN) with parameters (flow, pressure, temperature, level) - the exam tests application, not just definitions
4Distinguish DSEAR gas zones by likelihood and duration: Zone 0 continuous (Category 1G equipment), Zone 1 occasional in normal operation (2G), Zone 2 abnormal and short-lived (3G), with dust equivalents 20/21/22
5For the 10 extended scenario questions, practise reading a plant scenario and identifying the failed barrier - permit-to-work, isolation standard, shift handover, MOC, alarm response, or overfill protection - because these questions reward tracing causation rather than recalling facts
6Contrast protection concepts the exam likes to pair: leading versus lagging indicators, bonding versus earthing, flash point versus auto-ignition, jet fire versus pool fire, explosion venting versus suppression, and catalytic versus infrared gas detection

Frequently Asked Questions

What is the NEBOSH HSE Certificate in Process Safety Management?

It is a joint NEBOSH and GB Health and Safety Executive qualification covering process safety leadership, management of process risk, process safety hazard control, and fire and explosion protection. It is aimed at supervisors, engineers, and safety professionals in process industries such as oil and gas, chemicals, plastics, and pharmaceuticals, and is the recognised successor to the withdrawn NEBOSH Oil and Gas Certificate (IOG).

What is the PSM1 exam format?

PSM1 is a 90-minute online multiple-choice exam of 40 questions, 10 of which are extended questions linked to process plant scenarios. It is remotely invigilated, can be taken from home or work, and is offered monthly. All questions are compulsory and the paper samples every syllabus element.

What score do I need to pass the NEBOSH PSM exam?

The pass mark is 60% - at least 24 of the 40 marks. There is a single Pass grade (no credit or distinction bands), and results are normally issued within 15 working days with the parchment following within 20 working days of a pass.

How much does the NEBOSH PSM certificate cost?

Fees are set by individual NEBOSH Learning Partners. Classroom and e-learning packages including exam registration typically run from roughly GBP 400 to GBP 700, while exam-only registration is around GBP 164. The taught course is usually delivered over four to five days.

How long should I study for PSM1?

NEBOSH specifies a minimum of 28 taught hours plus about 20 hours of private study - roughly 48 hours in total. Most classroom candidates attend a 4-5 day course and sit the online exam at the next monthly sitting; e-learning candidates typically spread study over 3-6 months.

Does the NEBOSH PSM certificate expire?

No. The certificate does not expire and no periodic re-examination is required, although employers in major hazard industries generally expect holders to keep their knowledge current with standards such as COMAH, IEC 61511, and EEMUA 191.

Is the NEBOSH PSM certificate the replacement for the NEBOSH Oil and Gas Certificate?

Yes. NEBOSH withdrew the International Technical Certificate in Oil and Gas Operational Safety (IOG) and positions the HSE Certificate in Process Safety Management as its successor, with broader coverage across all process industries rather than oil and gas alone.