An everyday exposure that can cause cancer
Diesel engine exhaust is a mixture of gases and fine particles — including diesel particulate matter (DPM) — and WorkSafe recognises it as a cause of cancer, alongside asbestos, silica and welding fume. The fine particles carry chemicals deep into the lungs. Outdoors it usually disperses, but it builds up in enclosed spaces like tunnels, workshops and underground mines. You must manage the risk so far as is reasonably practicable, led by cleaner plant and good ventilation.
Diesel engine exhaust is a complex mixture of gases — including carbon monoxide, nitrogen dioxide and sulphur dioxide — and diesel particulate matter (DPM): tiny carbon particles with hazardous chemicals (polyaromatic hydrocarbons) on their surface. DPM is so fine it behaves like a gas, stays airborne for a long time, and penetrates deep into the lungs.
WorkSafe lists diesel engine exhaust among the common carcinogens in New Zealand workplaces, alongside asbestos, respirable crystalline silica and welding fume.
Most outdoor work has low concentrations because exhaust disperses. The risk rises sharply where dispersal is limited: tunnels and trenches, underground mines (especially after blasting, and around loading and haulage), vehicle repair workshops, enclosed or poorly ventilated areas, and behind sight screens or acoustic barriers. Workers nearby can be exposed even if they do not operate the diesel plant themselves.
Short-term, high exposure irritates the eyes, nose, throat and lungs and can cause coughing, light-headedness and nausea; very high levels of exhaust can cause carbon monoxide poisoning. Long-term exposure worsens asthma and allergies, raises the risk of heart and lung disease, and can cause lung cancer and possibly bladder cancer.
| Level | What it looks like |
|---|---|
| Eliminate / substitute | Choose plant that does not run on diesel (electric or gas), or low-emission engines and fuels — check this does not introduce other risks. |
| Engineer | Local exhaust or tailpipe extraction, particulate filters and catalytic devices, and enclosed cabs with filtered air. |
| Administrative | Maintain engines well, stop unnecessary idling, keep non-essential people away, and provide indoor break areas away from pollution. |
| Monitor | Exposure monitoring where needed, and health monitoring — see exposure & health monitoring. |
Respiratory protection is the last line of defence, used to back up higher-order controls, not instead of them.
Record where diesel exhaust is a risk and keep your controls in one place. Book a demo and we'll show you how it works — free 30-day trial included.
Yes. WorkSafe recognises diesel engine exhaust as a cause of cancer and lists it among the common carcinogens in New Zealand workplaces, alongside asbestos, silica and welding fume.
Diesel particulate matter — the very fine carbon particles in diesel exhaust, with hazardous chemicals on their surface. It is so small it behaves like a gas, stays airborne and penetrates deep into the lungs.
In enclosed or poorly ventilated spaces where it builds up, such as tunnels, trenches, underground mines, and vehicle workshops. Outdoors it usually disperses and the risk is lower.
Short-term irritation and, at very high levels, carbon monoxide poisoning. Long-term it worsens asthma and allergies, raises heart and lung disease risk, and can cause lung cancer and possibly bladder cancer.
Lead with cleaner plant — electric, gas or low-emission engines and fuels — then ventilation and extraction, filtered cabs, engine maintenance, no idling, and keeping people away, with respiratory protection only as a backup.
