While smoking remains the leading preventable risk factor for bladder cancer, and indeed most cancers, a lesser-known but significant contributor is workplace exposure to carcinogenic chemicals. In the UK, Cancer Research UK (CRUK) estimates that approximately 6% of bladder cancer cases are linked to occupational exposure. Worldwide, this number jumps to as high as 20%, as highlighted by Alouini (2024) in a comprehensive study on urothelial bladder cancer.* This makes workplace exposure the second most preventable risk factor for bladder cancer after tobacco use.
A Closer Look at the Chemicals Involved
A variety of industrial chemicals have been identified as carcinogens associated with bladder cancer. Chief among them are aromatic amines, polycyclic aromatic hydrocarbons (PAHs), metalworking fluids, diesel exhaust, and perchloroethylene. These substances are frequently encountered in certain sectors, and many of them have been the foundation of industrial processes for decades.
Aromatic Amines – Legacy Risks in Modern Industries
Aromatic amines are perhaps the most infamous culprits. These chemicals were widely used in dye, textile, and rubber manufacturing. Although the UK banned the most hazardous aromatic amines in the 1970s and 1980s, exposure persists today, particularly in settings where workers are handling older machinery, outdated materials, or imported products from countries where regulations may be less stringent.
One of the challenges is the long latency period between exposure and diagnosis. It can take 20 to 30 years for bladder cancer to manifest after initial contact with a carcinogenic agent. This means that workers exposed decades ago may only now be facing the consequences, complicating efforts to trace the origin of the disease and seek compensation or treatment.
Polycyclic Aromatic Hydrocarbons (PAHs) – Hidden in Smoke and Soot
PAHs are another group of chemicals known to increase bladder cancer risk. These are formed during the incomplete burning of organic substances, including coal, oil, gas, wood, rubbish, and even tobacco. Industrial processes such as aluminium smelting, coal tar processing, and asphalt paving are significant sources of PAH exposure.
Workers involved in coking plants, carbon production, or any job requiring frequent contact with soot or combustion by-products are particularly vulnerable. Though modern safety standards have helped mitigate risks, the presence of PAHs in the environment remains a persistent hazard, especially in developing economies or poorly regulated industries.
Other Industrial Exposures – Metalworking Fluids and Perchloroethylene:
Metalworking fluids (MWFs) are used extensively in machining processes to cool and lubricate metal parts. These fluids can become contaminated with various substances, including nitrosamines, bacteria, and other potentially carcinogenic compounds. Workers who inhale aerosolised MWFS or come into direct skin contact over long periods may be at elevated risk.
Perchloroethylene, a solvent commonly used in dry cleaning, is also linked to bladder cancer. Although many dry cleaners have moved over to less toxic alternatives, those working in older facilities or exposed over long careers may still be at risk. Similarly, diesel exhaust – a mixture of gases and fine particles – is a well-documented carcinogen and a major concern for transportation, mining, and construction workers.
Who’s Most at Risk?
Certain occupations carry significantly higher risks of bladder cancer due to routine exposure to these harmful chemicals. These include:
- Dye, textile, and rubber workers
- Painters and printers
- Machinists and metalworkers
- Lorry drivers and diesel mechanics
- Dry cleaning staff
- Chimney sweeps and smelter workers
How to Mitigate the Risks?
Reducing workplace exposure to carcinogens is no mean feat and would need to involve legislation, employer responsibility, worker education, and healthcare support. In the UK, regulations such as Control of Substances Hazardous to Health (COSHH) provide a legal framework to minimise exposure. However, enforcement and compliance vary across sectors.
Employers must prioritise:
- Regular risk assessments
- Adequate ventilation and containment systems
- Personal protective equipment (PPE)
- Substitution of hazardous substances with safer alternatives
- Routine health screenings for high-risk workers
Workers, on the other hand, should be empowered with the knowledge to recognise hazardous conditions and advocate for safer practices. Trade unions and occupational health bodies play a vital role in bridging the gap between legislation and on-the-ground realities.
The Importance of Early Detection
Since many chemical-induced bladder cancers emerge decades after exposure, early detection becomes critical. People need to be made aware of the common symptoms, which include blood in the urine, frequent urination, and pain during urination. Unfortunately, these symptoms can be easily mistaken for less serious conditions, delaying diagnosis.
Healthcare providers should maintain a high index of suspicion when treating individuals with a history of industrial work. Diagnostic tools such as urine cytology, cystoscopy, and advanced imaging are essential for identifying bladder cancer in its earliest stages, when treatment is most effective.
*Alouini. Risk factors associated with urothelial bladder cancer. Int. J. Environ. Res. Public Health 2024, 21, 954
