Businesses Face Scrutiny Over Diesel Exhaust Exposure as Workplace Cancer Risks Remain a Concern

Businesses operating diesel-powered vehicles and equipment are facing continued scrutiny over the health risks associated with exhaust emissions, as occupational health research highlights the potential consequences of prolonged exposure in workplaces.

The Health and Safety Executive (HSE) has identified diesel engine exhaust emissions as a significant occupational health hazard, particularly in enclosed or poorly ventilated environments where fumes can accumulate.

The issue affects a wide range of industries, including transport, logistics, construction, manufacturing, vehicle maintenance and warehousing. Workers in distribution centres, garages, loading bays and industrial facilities may encounter diesel emissions as part of routine operations, sometimes without recognising the potential long-term consequences.

The International Agency for Research on Cancer (IARC), part of the World Health Organization, has classified diesel engine exhaust as carcinogenic to humans, placing it in Group 1 alongside other agents for which sufficient evidence of cancer-causing effects exists.

The classification followed a review of scientific research examining occupational exposure to diesel emissions, including studies of workers exposed over extended periods.

Christopher Portier, who chaired the IARC working group responsible for evaluating the evidence, said the findings demonstrated that diesel exhaust was a cause of lung cancer and warranted action to reduce exposure.

The research has particular significance for businesses because diesel exhaust contains a complex mixture of gases, vapours and fine particles, including substances known to cause cancer.

Unlike some workplace hazards that produce immediate injuries, the effects of diesel exposure may develop gradually. Employees can experience irritation of the eyes and respiratory system, while repeated exposure over many years can increase the risk of serious respiratory disease.

HSE guidance identifies several working environments where exposure can become particularly significant. These include vehicle repair workshops, warehouses, transport depots, construction sites and other locations where diesel engines operate close to employees.

One concern is the continued use of diesel-powered vehicles inside buildings or partially enclosed areas.

Forklift trucks, delivery vehicles, generators and other equipment may operate for extended periods in environments where ventilation is insufficient to disperse exhaust emissions effectively.

The HSE warns that harmful concentrations can develop quickly when engines are operated indoors without appropriate extraction, particularly during cold starts or intermittent running.

The regulator also cautions against relying on open workshop doors as a substitute for suitable ventilation arrangements, noting that doors may be closed during colder weather or when operational requirements change.

The risks can be especially pronounced in vehicle maintenance businesses, where engines are frequently operated while stationary for inspection, testing and diagnostic work.

HSE guidance recommends suitable exhaust extraction systems connected directly to vehicle tailpipes, with emissions discharged safely outside the workplace.

The regulator also identifies engine maintenance as an important consideration. Poorly maintained engines can produce increased emissions, while visible blue or black smoke may indicate mechanical problems that require attention.

However, the absence of visible smoke does not necessarily mean that exhaust emissions are harmless.

The wider implications for occupational health have been highlighted by HSE research into work-related cancer.

Historical estimates commissioned by the regulator identified diesel exhaust exposure as a contributor to occupational cancer deaths within the construction industry. The HSE has cautioned that these estimates reflect working conditions and exposures extending back several decades, during which engine technology and fuel standards have changed considerably.

Nevertheless, the regulator maintains that diesel exhaust remains a workplace hazard requiring effective control.

Businesses are also subject to obligations under the Control of Substances Hazardous to Health Regulations 2002, commonly known as COSHH.

These regulations require employers to assess risks arising from hazardous substances and implement appropriate measures to prevent or adequately control exposure.

For carcinogenic substances, employers must reduce exposure to as low a level as is reasonably practicable.

The requirements mean that businesses cannot rely solely on general workplace ventilation or employee awareness where more effective engineering controls are reasonably practicable.

Operational changes may also influence exposure levels. Increased vehicle movements, alterations to loading arrangements, additional machinery or changes to building layouts can affect how exhaust emissions accumulate and disperse.

The transition towards electric industrial vehicles and equipment offers another potential means of reducing exposure. Battery-powered forklifts and other electric alternatives eliminate diesel exhaust emissions at the point of use, although businesses must still assess the safety risks associated with the replacement technology.

For organisations operating occupational health and safety management systems under ISO 45001, the issue is relevant to hazard identification, occupational health risk assessment, operational control and monitoring of workplace conditions.

It also demonstrates the importance of considering long-term occupational disease alongside more immediate accident risks.

While incidents involving machinery, falls and workplace transport frequently attract public attention, exposure to hazardous substances can create serious consequences that may not become apparent until many years later.

The HSE's position is that diesel exhaust exposure must be prevented or effectively controlled wherever workers may be affected.

As businesses continue to operate vehicle fleets, industrial machinery and diesel-powered equipment, the management of exhaust emissions remains an important occupational health responsibility across the UK economy.

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