The NEBOSH NG1 open book exam is a 24-hour scenario-based assessment you complete from home or work. You’re given a workplace scenario and around 11 questions, and you have 24 hours to write your answers using any reference materials you choose. The exam isn’t testing whether you can find information — it’s testing whether you can apply NEBOSH principles to the specific scenario in front of you. Most candidates who fail aren’t beaten by the questions; they’re beaten by treating the exam as a research task instead of an applied judgement task.
If you’re sitting the NEBOSH National General Certificate, NG1 is the part most people worry about. It’s the theoretical unit, assessed by a 24-hour open book exam — and the open book format throws people more than they expect.
This guide covers what the open book exam actually involves, how it’s structured, the mindset that gets people through it, and the specific mistakes that fail candidates who otherwise know their material. It draws on 41 years of taking KeyOstas learners through NEBOSH assessments — including the open book format introduced in 2020.
NG1 is the first of the two units that make up the NEBOSH National General Certificate. It assesses your understanding of health and safety management principles — the legal framework, risk assessment, hazard identification, management systems, incident investigation, behavioural safety. The unit is examined through a single open book examination, abbreviated by NEBOSH as “OBE.”
The exam works like this:
The closing interview is an integrity check, not a re-test. We’ve covered it separately in our guide to the NEBOSH closing interview.
This is the single most important thing to understand about NG1, and the source of most failed attempts.
If your last formal exam was at school or university, your instinct is that “open book” means easier. You can look things up. There’s nothing to memorise. The pressure is off.
That instinct is wrong, and the exam is designed to expose it. The OBE doesn’t reward candidates who can find information. It rewards candidates who can apply NEBOSH principles to a specific workplace scenario, in their own words, with structured reasoning. The textbook will not give you answers to the questions in front of you. The questions are written precisely so that they cannot be answered by quoting course material.
The mindset shift: treat NG1 as an applied judgement task, not a research task. You’re not being asked what the law says. You’re being asked what someone in the scenario should do, why they should do it, and what would happen if they didn’t.
The OBE always opens with a workplace scenario — typically a company, an industry, an incident, or a situation. The scenario sets the context for every question that follows. Read it carefully. Read it again. Make notes on what’s distinctive about the workplace described, because the questions will assume you’ve absorbed those details.
You’ll then face around 11 questions. Each question carries a mark allocation, usually between 4 and 20 marks. The mark allocation tells you how much depth is expected — a 5-mark question wants a focused answer of perhaps three or four points, while a 20-mark question expects a structured argument across multiple dimensions.
Question types you’ll encounter:
The exact wording of each question matters. “Outline” doesn’t mean the same as “explain,” and answering an outline question with explanation-level depth wastes time. Answering an explain question with outline-level brevity loses marks.
The 24-hour window is generous, but only if you use it deliberately. Most successful candidates spend roughly:
| Stage | Time | What to do |
|---|---|---|
| 1. Read | 30–45 mins | Read the scenario twice. Read every question. Note the mark allocations. Identify which questions you can answer immediately and which need thinking time. |
| 2. Plan | 1–2 hours | For each question, write a brief plan — three to six bullet points showing what you’ll cover. This stage saves more time than it costs. |
| 3. Write | 8–12 hours | Work through your answers, scenario-anchored, in your own words. Take breaks. Eat. Sleep if you need to. |
| 4. Review | 2–3 hours | Read each answer back. Check it answers the question that was asked. Check it references the scenario. Check it’s in your own words. |
| 5. Submit | 30 mins | Format check, word count check, submit at least an hour before the deadline. |
That uses roughly 14–18 hours of the 24 available. The remaining time is buffer — for thinking, breaks, the inevitable point in hour 6 when you realise you’ve misread a question.
Don’t try to do the whole thing in one sitting. The exam was designed assuming you’ll work, rest, and return. Candidates who try to write 11 answers in a single uninterrupted block tend to produce weaker work in the back half of the paper than candidates who break it across two or three sessions.
NEBOSH uses a defined set of command words across all certificate-level assessments. Misreading the command word is one of the most common reasons candidates lose marks they should have earned. Here’s what each one is asking for:
| Command word | What it asks |
|---|---|
| Identify | Name or list relevant items. Brief, not detailed. Often used as the starting point for a longer question. |
| Outline | Give main points with brief explanation. Not just a list — but not a full argument either. Think “headline plus a sentence.” |
| Describe | Provide detail on what something is, looks like, or involves. More than outline, less than explain. |
| Explain | Make something clear by describing how or why. Demands reasoning, not just description. |
| Justify | Argue why something is true, valid or appropriate. Show your reasoning. Anchor in the scenario. |
| Comment on | Analyse — including agreement, disagreement, qualifications. The most demanding command word. |
If you do nothing else before the exam, learn these six commands and the difference between them. Mark allocation tells you depth; command word tells you shape.
This is the second-most-common reason candidates fail when they shouldn’t.
Imagine the scenario describes a small bakery with 12 staff, gas-fired ovens, late shifts, and a recent near-miss involving a slip on a wet floor. The first question asks you to “identify the main fire safety hazards in the workplace described.”
A weak answer lists generic fire hazards — electrical equipment, flammable materials, smoking. It would fit any workplace. It scores around half marks.
A strong answer identifies the gas-fired ovens (specific to this bakery), the flour dust on baking surfaces (specific to bakeries), the late-shift fatigue increasing chance of human error around hot equipment (specific to this bakery’s working pattern), and the wet floor near the ovens (linking back to the near-miss). It scores full marks because it’s anchored in this scenario.
The pattern: every answer should reference the scenario. If your answer would work for any workplace, it’s not the answer NEBOSH wants. Re-read the scenario between every question if you have to.
From 41 years of NEBOSH delivery, the same patterns come up again and again:
NEBOSH uses plagiarism detection. Copy-pasted answers — even from your course notes — get flagged. Your answers must be in your own words. Use your reference materials to remind yourself of concepts, then explain them as if you were talking a colleague through them.
Generic answers score half marks at best. Anchor every answer in the workplace described.
Outline questions answered with three pages of explanation. Explain questions answered with a four-bullet list. Both lose marks. Read the command word, then plan your answer to fit it.
Candidates who try to write the exam in a single sitting typically produce strong answers for questions 1–6 and rushed, thin answers for questions 7–11. The mark distribution often weights the back end of the paper heavily. Plan your time so the last questions get full attention.
The temptation to spend the first 8 hours looking everything up online is strong, and counterproductive. The exam isn’t a knowledge test you can win by gathering more information. It’s an applied judgement test. The materials are there for reference, not as the source of your answer.
Practical preparation that makes the 24 hours easier:
Submission is electronic. You’ll get a confirmation. Then there’s a wait of around 30–40 working days while NEBOSH marks the paper and arranges your closing interview.
The closing interview is a short video call where a NEBOSH-appointed examiner asks you to explain your answers — confirming the work was your own. We’ve written a separate guide to the NEBOSH closing interview covering what to expect and how to prepare.
Results typically arrive 50 working days after the exam window closes. Pass marks for NG1 depend on the version of the syllabus and the specific assessment, but the published pass standard sits around the equivalent of a low-distinction grade in academic terms — challenging but not extreme.
You can resit failed units. NEBOSH charges a resit fee separate from your original course fee. You’ll need to wait until the next available exam window — typically run quarterly. KeyOstas provides post-exam support and revision help to learners who need to resit, and the second-attempt pass rate is significantly higher than the first-attempt rate. Failing NG1 once isn’t the end of the road; it’s information about which areas need more work before the resit.
No. The open book format removes the memorisation challenge, but replaces it with a higher bar on applied judgement. NEBOSH publishes pass rates around 60–70% globally for the General Certificate, which suggests the exam is genuinely demanding regardless of format.
Yes — the exam is open to any reference materials, including online sources. But online searching during the exam tends to slow candidates down rather than help them. Concepts you’d look up online should already be in your course materials in clearer form.
Mark allocation is the guide. As a rough rule of thumb, allow about 50–80 words per mark. A 10-mark question deserves around 500–800 words of well-structured answer. NEBOSH does set a total word limit for the exam (currently 3,000 words across all answers), so being concise matters.
NEBOSH treats plagiarism as misconduct and may void the exam, prevent you from sitting again for a defined period, or in serious cases bar you permanently. The detection is automated and thorough. Don’t risk it.
No. NEBOSH explicitly prohibits AI-generated content in OBE answers, and uses AI-content detection alongside plagiarism detection. The closing interview is in part designed to expose answers that weren’t written by the candidate. Use of AI to draft answers risks being treated as serious misconduct.
Typically a few weeks after the exam, scheduled by NEBOSH directly with you. See our closing interview guide for what to expect.
The NG1 open book exam isn’t designed to be passed alone. The candidates who do best at NEBOSH consistently come from Learning Partners with experienced tutors, structured exam preparation, and post-exam support — not online courses without a tutor.
KeyOstas has been delivering NEBOSH qualifications since 1984 — 41 years of taking learners through the General Certificate, including the open book format introduced in 2020. We’re a NEBOSH Gold Learning Partner (Centre 009), the highest tier NEBOSH offers. Our first-time pass rate runs at 85% or above, well over the national average.
If you’re considering the NEBOSH National General Certificate, see current course dates and what’s included on the course page. Or call us on +44 (0) 3300 569534 if you’d rather talk it through.
