Diesel, petrol and exhaust fumes under COSHH
What diesel and petrol do to the skin and lungs, why engine exhaust needs controlling on site and in workshops, and what goes in the COSHH assessment.
What does a COSHH assessment for diesel cover?
A COSHH assessment for diesel covers two hazards: the fuel, which harms the skin and lungs, and engine exhaust fumes, which HSE links to lung cancer. Where petrol plant is used, petrol and its exhaust belong in the same assessment.
Diesel data sheets class the fuel as suspected of causing cancer, harmful if inhaled and irritating to the skin. It may be fatal if swallowed and it enters the airways. Petrol is classed as able to cause cancer and genetic defects. Diesel exhaust is a mix of soot and gases. Short exposure can irritate the eyes and airways; HSE says repeated exposure over many years can increase the risk of lung cancer.
COSHH requires a suitable and sufficient assessment before the work, then exposure prevented or, where that is not reasonably practicable, adequately controlled. The fire and explosion risk from fuel falls under DSEAR instead; see storing hazardous substances. The data sheet for the fuel comes from your supplier: see reading a safety data sheet. Exhaust fumes have no data sheet, so HSE guidance HSG187 fills the gap.
Where trades meet diesel, petrol and exhaust
HSE says the main source of diesel exhaust on a construction site is likely to be generators and heavy vehicles such as lorries, excavators and telehandlers. The risk rises with longer work in enclosed spaces and wherever there is blue or black smoke.
| Task or setting | How exposure happens | Main harm |
|---|---|---|
| Refuelling plant, generators and small tools from bowsers and cans | Splashes and spills on hands, arms and clothing; overfilled tanks; leaking nozzles | Skin irritation and dermatitis from diesel; a fire if petrol vapour meets a spark |
| Generators, pumps and plant run in basements, tunnels, sheeted areas or excavations | Exhaust collects where the air does not move | Eye and airway irritation; with petrol engines, carbon monoxide that can kill |
| Petrol cut-off saws and other petrol tools used indoors | Carbon monoxide builds up in rooms, trenches and enclosed spaces | Carbon monoxide poisoning: HSE says a few minutes can create levels that kill |
| Plant and vehicle workshops and depots | Engines run for testing or warmed up indoors; cold starts give white smoke; fuel drained from tanks | Exhaust irritation; skin contact with hot fuel and used engine oil; petrol fires |
| Forklifts, delivery vehicles and loading bays | Diesel trucks working indoors all day; lorries left running in a despatch area | Exhaust build-up across the whole building, including offices next to it |
| Car parks, gatehouses and pay booths on FM sites | Vehicles idling or queuing next to the workstation | Diesel and petrol exhaust, with carbon monoxide where most vehicles run on petrol |
HSG187 does not cover engine exhaust in confined spaces, where separate guidance applies. See the confined spaces risk assessment.
What fuel and exhaust do to health
Hazard statements come from the GB mandatory classification and from supplier data sheets. Check section 2 of your own supplier’s sheet, because blends differ.
Diesel fuel on the skin
Diesel data sheets carry H315, causes skin irritation, and warn that repeated contact dries and defats the skin. HSE says spillage onto the skin may cause dermatitis. See occupational dermatitis.
HSG187 Appendix 2Swallowed fuel in the lungs
Both diesel and petrol carry H304, may be fatal if swallowed and enters airways. Fuel drawn into the lungs while swallowing or vomiting can damage them. Data sheets say do not induce vomiting and call a doctor at once. Our practical advice follows: never siphon fuel by mouth.
GB MCL List; supplier data sheetsDiesel fuel over time
The GB mandatory classification for diesel fuel is Carc. 2, H351, suspected of causing cancer. Supplier data sheets add H332, harmful if inhaled, and H373, may cause damage to organs through prolonged or repeated exposure.
GB MCL List, entry 649-224-00-6Petrol and benzene
The GB mandatory classification for gasoline is Carc. 1B and Muta. 1B: H350, may cause cancer, and H340, may cause genetic defects. It applies unless the supplier shows less than 0.1% benzene. Benzene itself is classed Carc. 1A, a known human carcinogen, with a WEL of 1 ppm over 8 hours and Carc and Sk notations.
GB MCL List, entries 649-378-00-4 and 601-020-00-8, Note P; EH40 Table 1Exhaust: short term
Diesel exhaust irritates the eyes and airways. HSE says the irritation should stop in fresh air. It is worst with heavy white smoke, such as engines started from cold indoors with no controls.
HSG187 paragraph 11; HSE INDG286Exhaust: longer exposure
Longer exposure, especially to blue or black smoke, can lead to coughing, chestiness and breathlessness. HSE says repeated exposure over many years can increase the risk of lung cancer. HSE’s leaflet INDG286 says there is some evidence of this after about 20 years of repeated exposure. It says petrol exhaust does not carry the same risk.
HSE INDG286; HSE, Cancer and constructionConstruction deaths
HSE-commissioned research estimated that over 200 construction workers died prematurely in 2005 from diesel exhaust. HSE notes the estimate rests on exposures up to 50 years ago, and engines and fuels have changed since. It says the risks that remain still need controlling.
HSE, Cancer and construction: diesel engine exhaust emissionsCarbon monoxide
A colourless, odourless, tasteless gas from incomplete burning of fuel. Petrol engines generally produce more of it than diesel engines. It stops the blood carrying oxygen. Early signs are drowsiness, headaches, breathlessness and nausea, easily mistaken for flu or tiredness. HSE warns it can kill quickly and without warning.
HSE, Construction hazardous substances: carbon monoxide; HSG187 paragraph 5What the law asks for fuel and exhaust
The duties are COSHH’s general ones. The rows say which come from the Regulations and which from HSE guidance.
Assess before the work
The law requires a suitable and sufficient assessment of the risk to health before work that may expose employees, and the steps it identifies put in place. It must consider the supplier’s data sheet and maintenance work where exposure may be high. An employer with 5 or more employees records the significant findings.
Regulation 6(1), (2) and (4)Prevent first, then control
Exposure must be prevented or, where that is not reasonably practicable, adequately controlled. Substitution comes first. Then controls in order: work methods and engineering controls, control at source with ventilation, and personal protective equipment last.
Regulation 7(1) to (3)No exposure limit for exhaust as a whole
HSG187 says no WEL has been set for diesel exhaust as a whole, and the current EH40 lists none. Some gases in it have WELs: carbon monoxide 20 ppm over 8 hours and 100 ppm over 15 minutes, nitrogen dioxide 0.5 ppm and 1 ppm over the same periods. HSE says to control the exhaust as a whole, not one gas.
HSG187 Appendix 2; EH40 Table 1Petrol counts as a carcinogen and mutagen
Regulation 2 defines carcinogens and mutagens as substances meeting the criteria for category 1A or 1B. Petrol’s GB classification, Carc. 1B and Muta. 1B, meets both. Where exposure cannot reasonably be prevented, regulation 7(5) adds measures, including no eating, drinking or smoking in areas that may be contaminated. Petrol labelled H340 or H350 also falls under regulation 7(7)(c)(i): control is adequate only if exposure is as low as is reasonably practicable.
Regulations 2, 7(5) and 7(7)(c)(i); GB MCL List Note PDiesel fuel and exhaust are not carcinogens in COSHH terms
Diesel fuel is Carc. 2, outside regulation 2’s definition of a carcinogen, which covers categories 1A and 1B only. Schedule 1 does not list diesel exhaust. HSG187 (2012) says it does not meet the classification criteria, so regulation 7(5) does not apply. The EU set a limit for it in 2019 of 0.05 mg/m³, measured as elemental carbon. The current EH40 does not include that limit.
Regulation 2 and Schedule 1; HSG187 Appendix 2; Directive (EU) 2019/130Used engine oil is a listed carcinogen
Schedule 1 lists used engine oils, so regulation 2 makes them a carcinogen. Fitters who drain and change oil on plant and vehicles meet it. Where their exposure cannot reasonably be prevented, the regulation 7(5) measures apply. Under regulation 7(7)(c)(i), exposure must be as low as is reasonably practicable.
Regulation 2; Schedule 1; regulation 7(5) and 7(7)(c)(i)Fire and explosion: DSEAR
COSHH’s main duties do not apply where a substance is hazardous solely because it is flammable. The fire and explosion risk from fuel falls under DSEAR 2002. At work, HSE says the Petroleum (Consolidation) Regulations 2014 apply only where petrol is dispensed from a fixed tank into vehicle fuel tanks, as at filling stations. DSEAR covers storing and using petrol at every workplace.
COSHH regulation 5(1)(b); HSE, storing petrol safelyHSE’s exposure limits page says it has considered every outstanding EU limit and will introduce revised limits for only three. All three are for underground mining and tunnelling and already in EH40. See workplace exposure limits.
Controlling fuel and exhaust, in regulation 7 order
HSG187’s controls for diesel apply to petrol engines too, unless it says otherwise. Notes mark HSE guidance and our own practical advice.
Prevent or substitute
Use electric or battery tools and plant indoors and in enclosed areas. Site generators outside, in well-ventilated places where fumes disperse and cannot gather or drift into building openings. Change the method or layout so that exhaust is never released inside.
NoteHSE’s carbon monoxide page: never use petrol equipment indoors or in enclosed spaces unless the ventilation needs have been fully assessed, with expert advice.
Control at source
Fit a tailpipe hose that takes exhaust outside where engines must run indoors. Consider exhaust after-treatment, such as particulate traps and catalytic converters. Where petrol plant must run indoors, HSE says mechanical extraction venting outside will almost always be needed.
NoteTailpipe extraction is local exhaust ventilation. HSG187 says LEV should be thoroughly examined and tested at least once every 14 months. See LEV.
Ventilate the space
Open doors and windows before starting engines and keep them open while engines run. Add roof or wall extraction where natural air is not enough. HSE warns that doors shut in winter to keep heat in let exhaust build up.
NoteIn tunnels, HSG187 places small generators downwind of the workers.
Organise the work
Switch engines off when not needed and warm them up outside where possible. Keep engines serviced and report blue or black smoke. Keep the number of people near running engines, and their time there, to the minimum.
NoteHSG187 says blue smoke points to a worn or poorly tuned engine, and black smoke to a mechanical fault or an engine near its maximum speed.
Protect the skin
Wear disposable nitrile gloves when handling cold diesel. For hot fuel or oil handled briefly, HSE advises thermal gloves over a thin nitrile inner glove. Change out of fuel-soaked clothing, and wash hands and face before eating, drinking or leaving work.
NoteRefuel with the engine off and a spill kit to hand. That is our practical advice, matching the plant RAMS.
Respiratory protection last
HSE says RPE is a last resort for diesel exhaust. It must protect against both the gases and the particles. Nuisance dust masks, like those worn by cyclists, do not work against diesel exhaust.
NoteRPE needs the right filter and a face fit test. See face fit testing.
Check it works
Look for soot on walls and surfaces, a visible haze and complaints of sore eyes or throats. Each one is a sign that control may not be adequate. Where the assessment calls for it, measure exposure, with a strategy set by a competent person such as an occupational hygienist. HSE advises carbon monoxide detectors where appropriate.
NoteHSG187 suggests carbon dioxide above 1,000 ppm as an 8-hour average may indicate failing ventilation. It is a marker, not a limit.
Judging diesel exhaust exposure: HSE’s table
HSG187 Table 2HSG187 gives a quick way to judge exposure from what anyone can see on site or in a workshop. It is guidance for the assessment, not a legal test.
| Sign | Low | Medium | High |
|---|---|---|---|
| Haze and smoke | No visible haze | Occasional white, blue or black smoke | Permanent white, blue or black smoke |
| Soot | No visible soot deposits | Visible soot in certain areas | Heavy soot, especially near exhausts |
| Complaints | No complaints of irritation | Some complaints of irritation | All exposed workers complain of irritation |
| Carbon dioxide, 8-hour average | Much lower than 1,000 ppm | About 1,000 ppm | Greater than 1,000 ppm |
| What it means | Controls likely to be adequate | Check the controls are adequate | Controls not adequate; decide on a control strategy |
The carbon dioxide WEL in EH40 is 5,000 ppm over 8 hours. HSG187 uses 1,000 ppm only as a sign of poor ventilation. White smoke at a cold start clears as the engine warms; HSE says better maintenance will not reduce it.
Health surveillance, training and reporting
No formal health surveillance for exhaust
HSE guidance says COSHH requires no formal health surveillance for people exposed to diesel exhaust. Workers with concerns should raise them with management. Complaints of irritation may mean the controls have failed and need prompt action.
HSG187 paragraph 35Skin contact with fuel and oil
Regulation 11 makes health surveillance appropriate where a disease may be related to the exposure, is reasonably likely in the work, and can be detected by valid, low-risk techniques. Our reading: regular skin contact with fuel or used oil can meet that test for dermatitis, so the assessment should decide on skin checks. See health surveillance.
Regulation 11(2)(b); our readingInformation and training
Workers need to know the health hazards and how to use the controls. HSE says they should be able to spot failing controls, such as a poorly maintained engine or damaged extraction, and report them. See COSHH training.
Regulation 12; HSG187 paragraphs 37 and 38Reporting under RIDDOR
A doctor’s diagnosis of occupational dermatitis is reportable where the work involves significant or regular exposure to a known skin sensitiser or irritant. So is any cancer attributed to occupational exposure to a known human carcinogen or mutagen. An injury from working in an enclosed space is reportable if it needs resuscitation or admission to hospital for more than 24 hours.
RIDDOR 2013, regulations 4(1)(h), 8(c) and 9(a)Writing the diesel and petrol COSHH assessment
Start with a list: every fuel held, including diesel, petrol, two-stroke mix and engine oil, with each supplier’s data sheet. Section 2 gives the hazard statements and section 8 the exposure controls. Then list the tasks: refuelling, running plant, servicing and draining, and where each happens.
For exhaust, HSG187 sets out the questions to answer. How many engines run at once, and are they all needed? Are they idling or at full power? Where does the exhaust go? Is there visible smoke, haze or soot? Have people complained of irritation? Could electric or battery power replace the engine?
Record who is exposed, for how long, the controls chosen and who checks them. Review the assessment when the plant, the place or the work changes. The free COSHH assessment template has a field for each, and the COSHH risk assessment template covers engine exhaust among other site hazards.
Every data sheet to hand,
tied to the job that uses it.
In Unibuild, each hazardous substance holds its safety data sheet and its supplier, linked to the jobs, materials and purchase orders that use it. Review dates are tracked, every version is kept, and the current one is the one out on site.
When an auditor or a principal contractor asks for the COSHH register, it is a search by name or supplier, not a spreadsheet somebody else kept.
- A data sheet for every substance held with its supplier
- Tied to the job through the materials and purchase orders that use it
- Review dates tracked and every version kept
- Searched by product name or supplier
Free COSHH templates
Free to use and reuse, no sign-upDiesel, petrol and exhaust: common questions
Do diesel and petrol need a COSHH assessment?
Where do I get a safety data sheet for diesel or petrol?
Is diesel exhaust a carcinogen?
Is there a workplace exposure limit for diesel fumes?
Can you use a petrol generator or cut-off saw indoors?
What are the signs of carbon monoxide poisoning?
What gloves should be worn when handling diesel?
Do workers exposed to diesel exhaust need health surveillance?
Is petrol more hazardous than diesel?
How should petrol be stored at work?
Substances and diseases
Read in any orderSources
Great Britain law and HSE guidance, read on the dates above. Northern Ireland has its own COSHH Regulations.
- HSE HSG187, Control of diesel engine exhaust emissions in the workplace, third edition 2012 (PDF)
- HSE INDG286, Diesel engine exhaust emissions (PDF)
- HSE, Cancer and construction: diesel engine exhaust emissions
- HSE, Construction hazardous substances: carbon monoxide
- HSE INDG331, Safe use of petrol in garages (PDF)
- HSE, Overview: storing petrol safely
- HSE, The GB mandatory classification and labelling list
- The Control of Substances Hazardous to Health Regulations 2002, regulation 7, legislation.gov.uk
- The Control of Substances Hazardous to Health Regulations 2002, Schedule 1, legislation.gov.uk
- HSE EH40/2005 Workplace exposure limits, fourth edition 2020 (PDF)
The COSHH register,
tied to the job.
Unibuild keeps each substance’s data sheet and supplier against the jobs, materials and purchase orders that use it, with review dates tracked and every version kept.