Health and Safety ReportVolume 3, Issue 4 - April 2005

Occupational cancer is nothing new. History books report occurrences of occupational cancer as far back as 200 years ago. There are mentions of increased scrotal cancer in chimney sweeps, lung cancer in miners, and bladder cancer in dye workers. Over the past two centuries, there have been numerous such reports of "cluster cases" that linked cancer to specific times, places or occupations - some conclusively, some not.

Research has identified a number of other groups of workers at increased risk for cancer because of occupational exposures. This research is necessary not only to ensure a safe work environment, but also to identify environmental factors that may cause cancer in the general population.

A listing of occupational factors that may cause human cancer can be found in a series of monographs published by the International Agency for Research on Cancer (IARC). Since 1971, IARC, a World Health Organization agency headquartered in France, has published more than 85 volumes dealing with cancer risks from individual chemicals, and mixtures of chemicals, in selected occupations or industries. Of the more than 900 chemicals, groups of chemicals, industrial processes, occupational exposures and cultural habits that have been evaluated to date, IARC has identified 95 that are known to cause cancer in humans, as well as a further 66 considered probably carcinogenic to humans.

The National Institute for Occupational Safety and Health (NIOSH) in the U.S. has estimated that approximately 20,000 cancer deaths and 40,000 new cases of cancer each year in the U.S. are attributable to workplace hazards.

It is estimated that 2-8% of all cancer deaths in Canada are due to workplace hazards - slightly more than one-tenth of the number due to tobacco. While the overall percentage may seem relatively small, the numbers of cancer deaths due to occupation are significant - roughly 1000 in Canada per year. There are workers that may have a much higher risk of developing cancer than those not exposed to carcinogens at work. Among the industrial processes and occupational exposures that IARC lists as cancer causing are:

• Aluminium production
  
• Manufacture of Auramine
  
• Boot and shoe manufacture and repair
  
• Coke production
  
• Furniture and cabinet making
  
• Haematite mining (underground) with exposure to radon
  
• Involuntary smoking
  
• Iron and steel founding

Data about occupational cancers in Canada is inconsistent from one jurisdiction to the next. An active disease surveillance system and additional education of physicians and workers about work-related illnesses may help to improve reporting.

Meanwhile, what can be done?

Experts agree on one thing - there is no known safe level for carcinogens. If progress is to be made in controlling occupational cancers, preventive efforts must be concentrated on reducing the exposures of these workers.

In Canada, regulations under the Occupational Health and Safety Act require both assessment and control of particular chemical substances, some of which are known human carcinogens. British Columbia is currently the only region in Canada that requires all carcinogens to be substituted with less hazardous substances.

Occupational cancers are preventable, especially where substances used in the workplace are known carcinogens. Wherever possible, the carcinogen should be replaced with a less toxic material, and at the very least, through engineering and process controls in the workplace, exposures to carcinogens should be reduced to the lowest possible level. In the event this cannot be done satisfactorily, appropriate personal protective equipment should be used. Finally, steps should be taken to ensure that carcinogenic material is not discharged unchecked into the environment or brought home by workers on their clothing or through other means.

Workers have a right to know when they are working with carcinogens and must be told what to do to protect their health. In the fight against occupational cancer, caution is the best defense. With increased awareness, it is hoped that workplace policy and legislation will emerge to lead to new practices that will safeguard the workers of today and the future.

IARC Web site - includes links to the IARC Monographs on the Evaluation of Carcinogenic Risks to Humans

NIOSH Carcinogen List

Whether you work in an office without air conditioning or in a foundry, surrounded by vats of molten metal, working in a hot environment can be more than just unpleasant. It's a potential danger to your health.

How the human body responds to hot environments depends on several factors, including air temperature, relative humidity and air movement. How much heat is exchanged between the body and the environment also depends on our clothing, our general state of health and acclimatization, and our level of physical exertion - all of which are explained in detail in Working in Hot Environments: A Health and Safety Guide.

This 96-page publication by the Canadian Centre for Occupational Health and Safety (CCOHS) serves as a handy resource for health and safety committee members and representatives as well as supervisors, managers, engineers and other health and safety professionals.

Heat exposure can be controlled. The guide outlines how to use engineering and administrative controls for improving thermal comfort in the workplace, as well as recommended personal protective equipment and sample safe work practices.

A section on the different heat related illnesses, including heat strain and heat stroke, explains the seriousness of these potentially fatal conditions, how to recognize symptoms, and what to do if someone is exhibiting those symptoms.

The book guides the reader through health and safety law, outlining the employer's and the employee's rights and responsibilities when it comes to preventing heat stress. The reader will gain a good understanding of occupational exposure limits and thermal comfort guidelines under heat exposure standards, as well as how heat exposure is measured. A section on legislative authorities in Canada and the US lists contact information and web links for easy reference.

"The main purpose of this guide," say the authors, "is to emphasize the importance of developing safe work practices and implementing preventive measure to prevent and or minimize worker exposure to extreme heat."

A French-language edition of Working in Hot Environments: A Health and Safety Guide will be published this year.

More information on Working in Hot Environments: A Health and Safety Guide

For answers to your OSH questions, contact the CCOHS Inquiries Service, toll free at 1-800-263-8466.

No one really knows why occupational asthma affects a small percentage of workers and bypasses the rest. This respiratory disease is caused by certain dusts, fumes or vapours in the workplace that trigger an abnormal response in the worker's body. The worker may experience skin rashes, hay fever-like symptoms, or a combination of these symptoms.

The offending substance may be tobacco dust in a cigarette factory, tea dust in a tea plant, carmine at a cosmetics manufacturing plant, feathers in a plucking operation at a poultry plant, or the acrylates found in sealants and adhesives in an autobody shop, to name just a few. Occupational asthma has also been reported in the healthcare industry, in pharmaceutical plants, in the wood industry, and in just about any other industry with airborne substances.

The medical community is aware of two main types of asthma: allergic, where antibodies attach to specific cells in the lung and react with the offending substance, and non-allergic, where repeated exposure to an industrial chemical causes leukotrienes and other substances to be released in the lungs, causing narrowing of air passages. Asthma may develop weeks, months or years after exposure to the irritant substances.

Recently, another type of asthma - reactive airways dysfunction syndrome (RADS) - has reared its head in the workplace. In RADS cases, symptoms of asthma may develop suddenly, within 24 hours following the inhalation of irritating substances such as smoke, dust, fumes and vapours. Afflicted workers often report symptoms by the end of the day. Symptoms may persist for months or years, when the sensitized person is re-exposed to irritants. RADS is still a relatively rare condition, and one that health and safety experts are still working to better understand.

Attacks of difficult breathing, tightness of the chest, coughing, and breath sounds such as wheezing, are often a tell-tale sign of occupational asthma. Typically these symptoms are worse on working days, often awakening the patient at night, and improving when the person is away from work. While off work, asthma sufferers may still have chest symptoms when exposed to airway irritants such as dusts, or fumes, or when they exercise. Itchy and watery eyes, sneezing, stuffy and runny nose, and skin rashes may also be associated with asthma.

Although there are drugs that may control the symptoms of asthma, it is important to stop exposure before breathing problems become permanent. A well-maintained, properly fitted dust mask or respirator can help to control workplace exposure, as can engineering controls such as ventilation, or proper training in how to handle chemicals, avoid spills and practise good housekeeping at work. The only way to ensure there will be no further exposure, however, is to change jobs, or to replace dangerous substances with less harmful ones.

To view the full OSH Answers document on occupational asthma, visit: www.ccohs.ca/oshanswers/diseases/asthma.html

A young man with just a week of experience at the marina where he was working, was fatally crushed by a 30-ton tugboat.

The tug, suspended on two slings, had been lifted out of the water by a mobile boat hoist (straddle lift). The lift was in the process of transferring the tug to blocking in the yard. There were blocks in place under the bow and stern, and the young lift helper was placing a second block under the bow.

The lift helper, while kneeling close to a lifting sling and its attached metal connecting pin, was out of the direct sight of the straddle-lift operator. When the lift operator lowered the stern of the boat onto the stern block, the lifting sling adjacent to the lift helper slipped along the hull. The lift helper was struck by the sling and its metal connecting pin. He died of crushing injuries to the head.

The Health and Safety Centre has issued an alert to remind workers of safety practices that could have prevented this fatality. It gives recommendations, including identifying high hazard areas (pinch points), training workers to follow written safety procedures, and ensuring the lift coordinator keeps workers in the clear before the hoist is moved or attitude of the vessel or load is changed. The lift coordinator and workers on the ground should use hand signals or other effective communication, says the alert, and wear safety headgear where there is potential for head injury.

In another incident in British Columbia, a 64-year-old excavator operator with 30 years experience was working alone to build the log foundation of a cabin. He was lifting logs with cables attached to a hook on the bucket of his excavator. The excavator had no window glazing or guarding on the boom side, and the front window was open. Ropes attached to each end of the log were run through the open front window where the operator could control them.

When the operator leaned out the open boom side window to reposition a rope, he inadvertently moved the boom control lever. The boom dropped down, crushing his head between the lifting cylinder and the cab. Another excavator operator had been crushed in a similar incident, just two years earlier.

Worksafe BC recommends that operators never use equipment when a safeguard has been removed. The boom side window or guarding on an excavator protects the operator if the boom drops down. No one should sell or rent equipment that does not have the manufacturer's safeguards in place. Operators should work with a co-worker as necessary for their safety, or have someone check on them regularly.

Read the full reports:

Boom crushes excavator operator

Young worker crushed when boat shifts while being lowered

The International Labour Organization (ILO) estimates that at least 1.6 million people die each year around the world due to work-related diseases. That is equivalent to losing the population of Montreal annually to occupational disease.
Occupational disease is illness that results from the conditions, functions or environment of employment rather than from the ordinary risks to which the general public is exposed. Some time usually elapses between exposure to the cause and development of symptoms, and in some instances, symptoms may not become evident for 20 years or more.

Since 1964, the ILO has maintained a list of internationally acknowledged occupational diseases to serve as guidance for countries establishing their own national lists and to encourage them to include the ILO list of diseases; to harmonize policy development on occupational diseases and promote their prevention; and for additions to the list to serve as catalysts to extend preventive measures to control the use of harmful substances, and assist a better health surveillance of workers.

The ILO List of Occupational Diseases is being reviewed and may be updated. Dr. Shengli Niu, Senior Specialist on Occupational Health from the International Labour Office reviewed the proposed amendments to the list and their impact at CCOHS' Forum on Occupational Disease held in March in Toronto.

The ILO has two official lists: the first (updated in 1980) is annexed to Convention 121 which is legally binding for countries who ratified the convention. The second list was developed in the early 1990's and adopted in 2002 - annexed to Recommendation No. 194. The December 2005 ILO tripartite meeting of experts will propose an updated version to replace the 2002 list after the approval of the ILO Governing Body, which is expected to take place in March 2006.

The list needs to be regularly updated to reflect new risk factors, diagnostic technology, new diseases, increased recognition at the national level, and international development. The key criteria for updating the ILO list may include the strength of the exposure-effect relationship between a specific working environment and/or activity and a specific disease effect, the magnitude of the risk factors and the fact that a disease is recognized in many national lists.
Agents/Diseases to be considered for inclusion in the new list:

• Chemicals (pesticides?)
  
• Physical (electromagnetic fields?)
  
• Biological (Tetanu, Brucellosis HBV/HCV, TB, HIV?)
  
• Diseases by target organs (Mental and behavioural illnesses such as Post-Traumatic Stress Disorder due to stressful event or situation and Psychosomatic and Psychiatric Syndrome caused by mobbing, Musculoskeletal disorders?)
  
• Occupational Cancer (Arsenic, Beryllium, Cadmium , Erionite , Ethylene oxides , Silic, Hepatitis B Virus and C Virus?)
  
• Other Diseases (Miners' nystagmus)

Read ILO Recommendation 194

ILO list of occupational diseases