The acute hazards are the ones everybody already controls
Arc eye, burns, cylinder handling, flashback arrestors. Anybody who has served their time in this trade will get those questions right, and they are in the bank because the test asks them.
The one that actually shortens lives is fume, and the position on it changed. All welding fume, including mild steel, is now treated as a human carcinogen. That is not a tightening of an existing rule, it is a reclassification, and it means engineering control is required for indoor welding regardless of how short the job is.
Why that change catches experienced welders out
The trade was taught for decades that mild steel fume was a nuisance and stainless was the one to worry about. Stainless is still worse, because hexavalent chromium is a potent carcinogen and nickel is a respiratory sensitiser. But mild steel is no longer in a different category, and the practical consequence is that the ten minute job indoors needs extraction too.
Coatings make it worse again. Galvanising gives metal fume fever, which presents as flu hours after the shift and gets dismissed because it passes. Old paint may contain lead, and two pack coatings release isocyanates, which is why the coating comes off before the heat goes on.
Shielding gas is an asphyxiant and gives no warning
Argon and carbon dioxide are both heavier than air. In a vessel, a pit or the bottom of a tank they displace the air and leave nothing to breathe, with no smell and no sensation at all until somebody loses consciousness. Inert does not mean safe. It means it will not react while it fills the space you are kneeling in.
Empty containers are the dangerous ones
A drum or vessel that has held a flammable substance is at its most dangerous when it looks empty, because the liquid is gone and what is left is vapour in the explosive range. Rinsing with water does not clear it reliably. Isolation, draining, cleaning, gas freeing and a test are what make hot work on one acceptable, and cutting into an apparently empty container for scrap has repeatedly killed people.
The health hazards that arrive slowly
Grinding is one of the highest vibration magnitude activities in the industry, so a daily exposure limit is reached fast and hand arm vibration syndrome does not reverse once it establishes. Fabrication noise puts people above the upper exposure action value routinely. Neither announces itself on the day it happens, which is why both are examined.
Two pools, and only one of them is about your trade
Two papers of K questions from a bank of N share about K squared over N. Two pools feed the paper, a large core one and a small pipefitting and welding one, and only the second is about your trade. Both are shown above the test, and revision mode comes back to what you keep getting wrong. Everything runs in your browser.
Common questions
What changed about welding fume?
All welding fume, including from mild steel, is now treated as a human carcinogen. It used to be regarded as far less serious than stainless. The practical consequence is that suitable engineering control is required for indoor welding of any duration, rather than only for long jobs or exotic materials. It is the single fact most of the trade learned late.
Does a short job need extraction?
Yes. There is no duration threshold below which indoor welding stops needing control. The enforcement position is that indoor welding without effective extraction is not acceptable, and a dust mask is not RPE for fume.
Why is oxygen so dangerous if it is not flammable?
Because it makes everything else catastrophically more flammable. Clothing saturated with oxygen ignites from a spark and burns faster than anybody can get out of it, and oil or grease on a fitting can ignite spontaneously. That is why oxygen is never used to blow down clothing or to ventilate a space.
Why must an acetylene cylinder stay upright?
Acetylene is unstable under pressure on its own, so it is dissolved in acetone held in a porous mass. Lying the cylinder down lets acetone reach the valve and the equipment, which damages both and leaves the cylinder unsafe even after it is stood back up.
How many can I afford to get wrong?
Forty five out of fifty inside forty five minutes, so the margin is five wrong answers. Fifteen questions come from pipefitting and welding and thirty five from the core operatives chapters. The trade fifteen lean hard on one change most of the trade learned late, which is that all welding fume including mild steel is now treated as a carcinogen, so answering from thirty years of practice is exactly how people lose those marks.
Are these real CITB pipefitting questions?
No. CITB sells the live bank in GT100 and does not publish it, so nothing free is the real thing. These come from free HSE guidance, mainly the gas cylinder and welding fume material plus the welding health risks and electricity pages, and every answer links to the source. On the fume reclassification in particular that link is the point, because it is the answer people refuse to believe without one.
Does sitting this affect my operatives mock progress?
Yes, and separately from the other papers. Each test has its own key in your browser, so nothing you do on the operatives paper touches this record. The specialist pool is twenty eight questions with fifteen drawn per paper, giving about eight repeats on a second attempt, and the result says so instead of letting a familiar looking paper pass for revision.