In brief
Exposures such as asbestos, crystalline silica, benzene, hardwood dust, welding fume and diesel exhaust are among the agents the International Agency for Research on Cancer classifies as definitely carcinogenic to humans. Occupational cancers often appear decades after exposure, after the worker has left the job; for this reason, records showing what a worker was exposed to and for how long are kept for at least 40 years after exposure ends under the Regulation on Carcinogens.
Why are occupational cancers recognised so late?
A workplace accident is visible the same day. Occupational cancers, that is work-related cancers, often appear ten, twenty or even forty years after exposure begins. By the time of diagnosis the worker is usually at another workplace or has retired; and if the physician does not ask the patient which job they did years ago, and which dust or chemical they worked in, the link between the disease and the work is never made.
This delay has two consequences. First, the cost of a measure not taken today is paid years later; second, the only way to establish the link is through properly kept records. In this article we explain which exposures are associated with which cancers, what the latency period means, and which records must be kept and for how long. For the regulatory rules on working with carcinogens (substitution, closed systems, the list of exposed workers), see our article on rules for working with carcinogens and mutagens.
Which exposures carry a risk?
The International Agency for Research on Cancer (IARC) classifies agents according to the strength of the evidence that they cause cancer in humans. The agents below are on the list of Group 1 agents, which are definitely carcinogenic to humans, and are directly relevant to work commonly found in industry in Bursa and neighbouring provinces.
| Agent | Associated cancer | Examples of jobs where it occurs |
|---|---|---|
| Asbestos | Mesothelioma, lung, larynx, ovary | Demolition and renovation of old buildings, old brake and gasket work, removal of insulation |
| Crystalline silica (respirable) | Lung | Foundry, stone and marble processing, ceramics, abrasive blasting, concrete cutting |
| Benzene | Leukaemia | Fuel storage and filling, chemicals, some solvent uses |
| Wood dust | Nasal cavity and sinuses, nasopharynx | Furniture manufacturing, sanding, cutting |
| Welding fume | Lung | Welding and cutting work |
| Diesel engine exhaust | Lung | Forklifts and construction machinery indoors, garages, tunnels |
| Formaldehyde | Nasopharynx, leukaemia | Resin, chipboard and MDF production, laboratories |
| Hexavalent chromium and nickel compounds | Lung; for nickel, nose and sinuses | Chrome plating, stainless steel welding |
| Vinyl chloride | Liver (angiosarcoma) | PVC production |
| Certain aromatic amines | Bladder | Dye and pigment production, old rubber work |
| Solar radiation | Skin cancers | Construction, agriculture and other outdoor work |
Asbestos cancer: mesothelioma and lung
Asbestos is the main cause of mesothelioma of the lining of the lungs and abdomen. Although asbestos is no longer used today, it remains in old buildings as roofing sheets, pipe insulation and flooring material; the risk arises when these materials are removed or demolished. The occupational exposure limit for asbestos is 0.1 fibres/cm³ and records are kept for 40 years. For removal rules see our articles on asbestos removal work, and for how to recognise suspect material in old buildings, suspected asbestos materials in old buildings.
Benzene and leukaemia
Benzene affects the blood-forming system and can cause leukaemia; the link between benzene and leukaemia is one of the best known among occupational cancers. Annex 2 of the Regulation on Health and Safety Measures in Work with Carcinogens or Mutagens sets the 8-hour limit value for benzene at 1 ppm (3.25 mg/m³) and notes that exposure can also occur through the skin. This means that gloves and skin contact must also be part of the control plan. For exposure in the fuel sector, see our article on fuel station workers.
Occupational lung cancer: silica, welding fume and diesel exhaust
Lung cancer is the type of occupational cancer associated with the largest number of agents. Crystalline silica, welding fume, diesel exhaust, chromium and nickel compounds and asbestos are on this list. Smoking increases this risk further; so in dusty and fume-laden jobs, support to stop smoking is also part of health surveillance. For details, read our articles on crystalline silica dust and the health effects of welding fume.
Wood dust and nasal and sinus cancer
Work involving exposure to hardwood dust is listed among carcinogenic processes in Annex 1 of the Regulation on Carcinogens, and Annex 2 gives a limit value of 5 mg/m³ for hardwood dust; if hardwood dust is mixed with other wood dusts, this value applies to the whole mixture. In Bursa's furniture-producing districts, İnegöl above all, this increases the importance of dust extraction systems and measurement; see wood dust and dust extraction.
What does a long latency period mean?
The time between the start of exposure and the appearance of cancer is called the latency period. Mesothelioma often appears 20 years or more after exposure; lung cancers also involve decades. Benzene-related leukaemia, by contrast, can appear sooner. This picture has three implications for the workplace:
- Today's healthy picture is misleading: The absence of disease among workers today does not show that the exposure is harmless.
- Records outlive employment: The disease can appear years after the worker leaves; records must remain accessible until then.
- The occupational history is vital: The answer to the diagnosing physician's question "where have you worked?" is only meaningful if the worker has information about their exposure.
For how an occupational disease is diagnosed and what the liability period means, see our articles on what an occupational disease is, diagnosis and notification and the list of occupational diseases.
Exposure records: which record, and for how long?
The value of a record depends on its content. A good exposure record includes: the worker's name and job, which department they worked in and between which dates, the substance or process they were exposed to, workplace measurement results and dates, the protective measures used and health surveillance results. We plan workplace measurements with authorised laboratories; for how measurement results are compared with limit values, see our article on occupational exposure limit values.
Health surveillance and notification
Workers exposed to carcinogens are placed under health surveillance before exposure and at regular intervals afterwards. In health surveillance, the worker's occupational and medical history is recorded, examinations are carried out and, where possible, biological monitoring is applied (Regulation on Carcinogens, Art. 16 and Annex 3). The regulation is clear on two points:
- If a health problem is found to result from carcinogen exposure, the employer reviews the risk assessment and measures and implements measures, including assigning the worker to another job without exposure; if the physician considers it necessary, other similarly exposed workers are also placed under regular surveillance.
- All cancer cases with a provisional diagnosis of having been caused by carcinogen exposure are notified to the relevant institutions under Art. 14 of Law No. 6331 (Art. 16/5).
For how chest X-rays are read in dusty jobs with a risk of lung cancer and pneumoconiosis, see our article on chest X-rays under the ILO classification, and for the path to follow when an occupational disease is suspected, see the physician's role when an occupational disease is suspected. Working with carcinogenic drugs in the healthcare sector is a separate topic; see antineoplastic drug preparation.
Order of priority in prevention
The order of priority in preventing occupational cancers does not change: first eliminate the agent or replace it with a less hazardous one, then use closed systems and local exhaust ventilation, then work organisation, and finally personal protective equipment. Since no safe level of exposure can be demonstrated for many carcinogens, the goal is not to stay below the limit value but to reduce exposure to the lowest possible level.
In workplaces where carcinogenic agents are present, we draw up the exposure inventory as part of risk assessment, and run health surveillance and record-keeping through our workplace physician service. For risks specific to the chemicals and plastics sector, see our chemicals and plastics sector page, and to track measurement and examination dates, use our OHS calendar tool.
Frequently Asked Questions
Which cancers can be considered occupational cancers?
Cancers with a scientifically demonstrated link to an agent in the workplace. The best-known examples are mesothelioma and lung cancer with asbestos, leukaemia with benzene, nasal and sinus cancer with hardwood dust, and lung cancer with crystalline silica and welding fume.
How long are the records of a worker exposed to a carcinogen kept?
Under the Regulation on Carcinogens, for at least 40 years after exposure ends. If the workplace closes, the records are handed over to the SGK provincial directorate.
What happens if an occupational cancer appears years after leaving the job?
The disease can still be assessed as an occupational disease. To do so, it must be shown in which job, to what and for how long the worker was exposed; this is only possible with retained exposure and health records.
Is exposure below the limit value safe?
Not always with carcinogens. Since no safe threshold can be demonstrated for many of these substances, the goal is not merely to stay below the limit value but to reduce exposure to the lowest possible level.
A physician assigned for the time your hazard class requires: pre-employment and periodic examinations, fitness-for-work reports and health surveillance.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.