Evidence of the harmful effects of diesel emissions is growing, resulting in it being likened to another toxic ‘timebomb’. These developments are likely to require corporates and their insurers to reconsider their approach to this developing risk.

A new inquest into the passing of a child who died from asthma was recently ordered, following evidence that the death may be linked to nearby pollution. This could be the first example of air pollution being officially recorded on a death certificate in the UK.

For those with an occupational interest, current claim levels and case law suggest any timebomb has yet to go off, but the harmful effects of diesel exposure are becoming more widely understood. Unions are involved in raising awareness and supporting members in bringing claims. Claims management companies and solicitors are also expected to develop a cohort of claims.

While there are barriers to significant levels of claims currently, legislative bodies internationally are considering closer regulation of occupational levels. With more stringent limits, it will be easier for those exposed to identify companies whose inadequacies may have caused their illness.

In 2012, the Agency for Research on Cancer (IARC), part of the World Health Organization, reclassified diesel engine exhaust emissions (DEEEs) as carcinogenic to humans. The decision followed evidence suggesting long-term exposure to DEEEs increases the risk of lung cancer.

The IARC concluded that exposure may increase lung injury and exacerbate asthma and chronic obstructive pulmonary disease. What is not currently clear is how these conditions may affect susceptibility to lung cancer, or how potent DEEEs are in causing such illnesses.

In the UK, workplace DEEEs levels are regulated by the Control of Substances Hazardous to Health Regulations (COSHH). Employers are required to assess the danger of such substances and to minimise their exposure, risking prosecution for failing to do so.

Risk assessments of potential levels of exposure are also required, as well as implementing control measures. Currently, this may involve substituting diesel with a safer fuel or using electric vehicles. If an assessment identifies unavoidable risk, employers must consider what controls are necessary to reduce that risk, including changes to working practices to eliminate or mitigate the danger.

Under COSHH, DEEEs are not recognised as carcinogenic, but are defined as a “substance hazardous to health”. While some individual components of diesel are already deemed carcinogenic and subject to workplace exposure limits (WEL), there remains no specific WEL for diesel fumes in the UK.

The European Union recently agreed to amend the Carcinogens and Mutagens Directive (CMD), adding a WEL for DEEEs, which will require employers to keep emissions under 0.05 mg/m³. The amendment, which will apply generally from 2023 (and 2026 for underground mining and tunnelling), relates to all diesel engines, without distinguishing between sources of emissions.

The move also means that DEEEs will be listed as carcinogenic under the EU Classification and Labelling Regulations. If the CMD is transposed to UK law, this will change the classification of DEEEs to that of a human carcinogen under COSHH. Notwithstanding any changes to this regulatory framework, it is current best practice for employers to implement sensible safeguards where there is frequent exposure to diesel emissions and other pollutants.

While claims volumes are increasing, they have not approached levels near that of traditional risks, such as asbestos or noise-induced hearing loss. The current barrier for many claims will be proving negligence on the part of employers and that exposure caused the injury.

Latency periods are also relatively long and, therefore, it may be some time until significant claim numbers are seen. Equally, until there is a clearly defined WEL, claimants will continue to struggle to advance clear allegations of negligence against employers. Faced with this difficulty, some claimants are bringing claims utilising alternative causes of action.

One claimant recently alleged exposure to DEEEs and ammonia that had been added to the fuel, caused him to develop occupational asthma. The allegation that ammonia exposure caused/exacerbated the asthma was perhaps raised due to the clearly defined occupational exposure limits of this compound. In the absence of expert evidence refuting this allegation, this may have presented a credible argument for the claimant. Further innovative pleadings are to be expected in future.

The focus of claims in this area to date has been on the risk of respiratory illnesses. However, recent studies suggest that exposure increases the risk of other types of cancer and neurological illnesses.

King’s College London recently found that as many as one in 14 cases of dementia, including Alzheimer’s disease, could be attributable to air pollution. Those living in the most-polluted areas were 40% more likely to be diagnosed with dementia. Harvard scientists also found that men with higher exposure to diesel emissions for five to ten years were at least 20% more likely to develop motor neurone disease than those with no exposure.

As scientific understanding becomes clearer, insurers and risk managers must be prepared for occupational exposure claims for a wider range of illnesses. Hyperbole of timebombs aside, there is no doubt that exposure to DEEEs carries a risk requiring suitable risk management and appropriate preventative guidelines.

While there are clear moves to restrict exposure to DEEEs both in the workplace and beyond, recent research shows that the risk extends beyond respiratory illnesses. This is likely to result in a larger cohort of potential claimants in the future. Accordingly, risk managers and insurers would be well advised to consider and monitor the prospect of exposure to DEEEs within their business and among policyholders.