Carcinogens are substances, mixtures and process-related chemical compounds which are capable of causing cancer or promoting the occurrence of cancer through inhalation, ingestion or skin contact.

The most common carcinogens in the workplace are:

  • chromium (VI) compounds
  • nickel and arsenic and their inorganic compounds
  • polycyclic aromatic hydrocarbons (PAHs), such as benzo(a)pyrene, coal tar, soot and coal tar pitch
  • benzene
  • cadmium and cadmium compounds
  • asbestos
  • welding fumes and fine dusts from working stainless and acid-proof steel
  • diesel exhaust
  • environmental tobacco smoke
  • hardwood dust
  • quartz
  • formaldehyde
  • PCB compounds
  • solvents, such as benzene and 1,2-dichloroethane
  • vinyl chloride
  • 1,3-butadiene
  • ethylene oxide.

Persons working in the following professions have the most exposure to carcinogens:

  • metal processing plant operators
  • other construction workers
  • aircraft engine mechanics and repairers
  • mineral and stone processing plant operators
  • miners and quarriers
  • incinerator and water treatment plant operators.

Carcinogens are also involved in the following work methods:

  • manufacture of auramine
  • work involving exposure to polycyclic aromatic hydrocarbons (PAHs)
  • work involving exposure to carcinogens from combustion processes
  • work involving exposure to dusts, fumes and sprays produced during the roasting and electro-refining of copper-nickel mattes.
  • strong acid process in the manufacture of isopropyl alcohol
  • work involving the worker’s exposure to hardwood dust
  • work involving exposure to used engine oils
  • work involving exposure to crystalline silica dust
  • work involving exposure to carcinogens that are cytotoxic agents in the Anatomical Therapeutic Chemical (ATC) classification
  • welding and flame cutting of stainless steel
  • work involving exposure to diesel engine exhaust gases.

Exposure may lead to cancer

Cancer is a disease involving uncontrolled cell growth with the potential to spread from the original location to other parts of the body. The development of cancer usually includes a long latency period: the period between the initial exposure to a carcinogen and the cancer diagnosis is usually between 10 to 40 years. The development of cancer is a long chain of events. Usually, the human body repairs and fights mutations to prevent the cancer.

Binding exposure limit values

Some carcinogens have binding limits for maximum exposure at work. Further information is available on page Limit values.

Employer’s reporting obligations

It is the employer’s duty to report all employees exposed to carcinogenic substances and methods at work to the Finnish register of workers exposed to carcinogens (the ASA Register). Further information is available on page Register of exposed workers.

Carcinogens: classification and labelling

Carcinogenic substances and mixtures can be identified by the fact that they are classified as category 1A or 1B carcinogens under the Classification, Labelling and Packaging (CLP) Regulation. These substances and mixtures are also labelled with a hazard statement (H) and a hazard pictogram:


CLP Regulation (EC)

No 1272/2008


May cause cancer


Hazard symbol for carcinogenic substances in accordance with the CLP Regulation.

Substances and mixtures suspected of causing cancer are classified as category 2 carcinogens under the CLP Regulation. They are also labelled with a hazard statement (H) and a hazard pictogram:


CLP Regulation (EC)

No 1272/2008


Suspected of causing cancer


Hazard symbol for carcinogenic substances in accordance with the CLP Regulation.

Facilities and signsA human figure explodes from the inside.

Facilities where carcinogens are handled must be clearly indicated by signs.

A good way of indicating these facilities is by using the health hazard symbol (GHS08 sign) with the text: “Carcinogenic substances in use!”.