Don’t smoke. Exercise. Limit your alcohol intake. Cut down on red meat.

When it comes to avoiding cancer, this is very good advice, but it would still leave you vulnerable.

Did you know you could get lung cancer without having ever smoked a cigarette, or having inhaled any second-hand smoke?  Many carcinogens exist in the environment or are created in the course of commercial activities, but you may not know they even exist.

Today is World Health Day and the world is focusing on non-communicable diseases such as diabetes and cancer. Although the theme for this year is “Beat Diabetes”, Nation Newsplex continues to shed light on cancer, the third biggest killer disease in Kenya. From 2010 to 2014, the number of cancer deaths per 100,000 people increased by six per cent.

Cancer is the third biggest killer disease in Kenya after malaria and pneumonia and in 2014 14,175 people died of the disease.

According to the International Agency of Research on Cancer of the World Health Organisation (IARC), 29 different agents can cause lung cancer in human beings.

In many towns across Kenya, you are likely to find carpenters lining the side of the road, hoping a customer will buy their beds and drawers. As they measure and chop and sand and varnish, they risk inhaling fine particles of wood dust, which has been proven to cause cancer of the nasal cavity. Modern wood cutting machines produce especially fine particles.

COUNTING CARCINOGENS

Shoemakers are also at risk of cancer from inhaling leather dust, which is created during shoe manufacture, and from inhaling solvents such as benzene. Your trusty cobbler could inhale leather dust when scouring the shoe before applying glue. Leather dust also causes cancer of the nasal cavity, according to the IARC.

Four out of five cancer cases in Kenya are diagnosed in the advanced stages, suggesting that many people are not tested early enough, even if they may have been exposed to carcinogens.

Just how many carcinogens are there, and what level of cancer risk do they pose? The International Agency for Research on Cancer (IARC) of the World Health Organisation classifies carcinogens. 

As of February 22, 2016, the IARC had classified 118 agents as known human carcinogens, meaning there is sufficient evidence of them causing cancer in humans.  An agent can either be a substance or an occupation that exposes a person to one or more carcinogens.

Wearing the proper protective equipment is an important part of mitigating cancer risk. In fact, the Occupational Health and Safety Act 2007 recognises the risk of exposure to carcinogens at work, and in the Second Schedule, designates a list of conditions, including cancers, as Occupational Diseases.

However it is not clear that workers at risk know they are exposed. According to Mr Anthony Kwache, the National Chairman of the Kenya National Alliance of Street Vendors and Informal Traders (KENASVIT), most carpenters don’t know the risk that wood dust poses. “Some of them put on protective masks, lakini wengine ni kawaida kwao (to others it is just normal),” he said.

He also says the Ministry of Health and the Ministry of Industrialisationshould do more to sensitise workers. “Unless you do sensitisation, how can people be aware? ” he asks. Mr Kwache also thinks such work should be restricted to specific locations, so that fewer people are exposed to the risks.

Aflatoxin, which in Kenya results from the improper drying of maize, causes liver cancer in humans. Formaldehyde, which is used as a preservative and often added to illicit alcohol, causes leukaemia, a cancer that starts in the bone marrow and affects blood cells.

Arsenic, a toxic heavy metal, occurs naturally in groundwater in many parts of the world, and an arsenic compound, chromated copper arsenate, is used as a wood preservative. According to the IARC, there is sufficient evidence that arsenic causes cancer of the lung, skin and urinary bladder, and limited evidence that it causes cancer in the prostate, kidney, liver and bile duct.

Workers who make pigments and dyes risk being exposed to cadmium, an extremely toxic heavy metal which causes cancer of the lung, kidney and prostate, benzidine which causes bladder cancer, and hexavalent chromium, which causes lung cancer.

DIESEL EXHAUSTS

Asbestos, once valued for its insulation, is no longer used for roofing because it is known to cause lung cancer. In 2013, the National Environmental Management Authority (NEMA) released guidelines for the disposal of asbestos. However, there does not seem to be any public program aimed at accelerating the removal of asbestos around the country.

Diesel engine exhausts are a known carcinogen that affect a particularly wide of people.  Mechanics, bus and truck drivers, dock workers, fuel station attendants, operators of excavating machines, professional drivers and railway workers are all at risk of lung cancer, according to the Canadian Centre for Occupational Health and Safety.

Diesel fumes, together with particulate matter, constitute outdoor air pollution, which is a proven carcinogen that will only get more plentiful as Kenya gets increasingly urbanised. According to the IARC,the causes of outdoor air pollution include burning of rubbish, loose-surface dirt roads, wood and charcoal stoves, and congested traffic.

In addition to proven human carcinogens, another 79 agents are classified as probably carcinogenic, meaning that there is limited evidence that they cause cancer in humans but sufficient evidence that they cause cancer in animals.

Kenya has seen more frequent reporting of lead poisoning in recent months, particularly at Owino Uhuru in Mombasa and in Nakuru County. Workers usually come into contact with lead when they extract the metal from used lead acid batteries. Children may come into contact with lead particles in homes where lead paint is used.

Lead is an extremely toxic heavy metal that poisons the central nervous system and can have irreversible, adverse effects on intelligence. In addition, the IARC says there is limited evidence linking lead to stomach cancer in humans.

The risk of cancer follows many Kenyans home from polluted streets to homes that use fuel from wood. IARC classifies the domestic consumption of biomass fuel, such as firewood, as a probable carcinogen, meaning there is limited evidence its use can cause lung cancer in humans.

Two hundred and ninety agents are classified as possibly carcinogenic, meaning that there is limited evidence that they cause cancer in humans, but less than sufficient evidence that they cause cancer in experimental animals.

Another 501 agents cannot be classified as to their cancer risk, while one is classified as probably not carcinogenic.