MRO Magazine

Handle with Care: Dealing with toxic thallium sulphate


November 14, 2001
By PEM Magazine

Thallium sulphate is an odourless, tasteless, colourless compound that dissolves in water. Originally developed as a rat poison in the 1970s, thallium sulphate is currently used in the manufacture of electronic equipment, infrared light detectors and medical imaging devices. It is also a naturally occuring by-product of coal burning and lead smelting.

In industrial settings, thallium is highly toxic and can cause nerve, kidney and liver damage if inhaled or absorbed through the skin.

If it’s so dangerous, then why, were maintenance workers in Teck Cominco’s lead smelter in Trail, B.C. exposed to the substance without their knowledge?

When some of the 65 carpenters and welders who worked in the smelter during a scheduled maintenance shutdown in August fell ill, the incident made national headlines. Eventually all of the workers underwent tests at area hospitals. In a statement released to the media, officials with Teck Cominco admitted to not informing its contract workers about the presence of thallium in the smelter where they were working.


"It’s a terrible situation. I feel sick about it," Bill Van Beek, general manager of the smelter told the CBC when the story emerged. "It’s there, and we’ve got to…look after the workers."

Since the substance can be absorbed through the skin, the workers say if they had known it was present, they would have taken better precautions. As it was, all they had were gas masks to keep them from inhaling the dust.

The debacle acts as a reminder to all plant managers and maintenance professionals the importance of establishing a safe chemical handling regime in their plants.

Chemical spills, accidental chemical mixtures, and unprotected exposure to dangerous substances in the workplace commonly bring with them a number of problems that can easily spiral out of control. The community wants to know why it was unaware of the presence of hazardous substances; employees question safety issues and employer loyalty; and the affected firm has to fight to make sure such problems do not result in corporate turmoil. All of this can be avoided if manufacturing operations take some necessary steps before handling chemicals of any type. To ensure safety, a firm must recognize potential dangers, create and adhere to procedures, train users and educate the community of chemicals in use, and invest in precautionary measures and technologies.

Recognizing danger
Before being able to safeguard a plant and its workers from danger, it is crucial to first recognize when a danger is present. The keys to detection are to follow all of the regulations directly applied to the chemical at hand, and to develop a strong understanding of the hazards currently or potentially in the workplace. According to Scott Berger, senior project manager of the American Institute for Chemical Engineers’ Center for Chemical Process Safety: "When a firm disregards a potential chemical hazard is when there should be a concern. Any chemical can be dangerous if it not controlled to its level of hazard, so the moment that you decide something is not dangerous, that is when you are putting yourself and your employees at risk."

When looking for potential hazards, take into consideration that little is known about the effect on human health of some 30,000 chemicals in wide use today. Furthermore, the United States Environmental Protection Agency recently issued a list of approximately four hundred extremely hazardous substances. Chemical scares involving DDT, Aldrin, Dieldrin, Thallium and other substances trigger concerns about community access to information on hazardous chemicals. Nationwide, coalitions have formed to fight for access to information on chemical hazards and for protection from these hazards.

Although many believe that the answer is to force the chemicals industry to prove products are safe, relying entirely on this strategy would be largely inadequate. It is true that under the WHMIS regime every chemical producer must provide a complete and regularly updated Material Safety Data Sheet (MSDS), but the individual producers can’t be sure of what other chemicals will be used in the end user’s location.

Therefore, plant personnel must take responsibility to research the chemicals in place and ascertain that the chemicals, on their own or in combination with other substances, will not inadvertently cause harmful reactions.

Establish, implement and adhere to procedures
Handling chemicals should be done in as regimented a manner as the ISO standards set for manufacturing and inspecting of products. After recognizing any potential dangers it is imperative to establish safety procedures. The documentation aspect is undoubtedly very resource-demanding, but should never be avoided.

The research portion of this task can be cut down significantly by finding a supplier with a good safety record and strong procedures in place. Upon selection of a chemical supplier, request specific recommendations and help in writing procedures. "In many cases, the supplier or chemical producer has dealt with any problems that you have or will potentially come across throughout the R&D of the chemical," said Berger. If the chemical firm does not provide you with all of the information you require, the American Institute of Chemical Engineers’ Web site ( also provides a wealth of resources for any firm with chemical questions.

Be sure that the procedures you establish fall in line with the "right-to-know" concept. This involves giving workers access to information about the hazardous materials in their workplaces. Various industry standards for chemical labelling in the workplace and MSDS now exist to serve as tools to communicate chemical hazards to workers. Internationally, guidelines now exist on organizing community emergency preparedness, site-specific emergency planning, and criteria for determining whether a substance is hazardous, and profiles of hazardous substances.

Establishing and implementing procedures is only the first portion of a successful regimen — adhering to procedures is the true key to success. Keeping in mind that anywhere a chemical is in use that there is a risk, be ruthless about maintenance and every once and while go back and ask if there is anything at risk.

Education, education, education
Education is the key. Make sure that all employees thoroughly understand and accept the established procedures. The is especially important since the least experienced and least knowledgeable employees tend to be the ones initiating an incident, it is not possible to over-train employees on chemical hazards. Training helps to safeguard your facility from such travesties. Educate yourself and neighbours and train your staff so that everyone is aware of what is going on. Although every chemical should be covered, substances of special concern, such as those that cause cancer and may potentially lead to fatalities, should trigger the most detailed training.

Never be completely satisfied with the knowledge obtained and always be on the lookout for further updated information. Despite information-gathering initiatives Canada, Europe and the United States, no one country has yet been successful in overcoming the huge gap in knowledge of substances.

A combined effort between the governments of Canada, U.S. and the members of the EU have identified chemicals that cause irreversible damage to the environment and human health.

Do not take community relations lightly especially dealing with the emergency response team (ERT) in your immediate area. ERTs may actually serve as an additional resource for further information, and by educating these units on the chemicals in use in your operation, it is easier to safeguard your plant as well as your reputation should an unfortunate event occur. You have to prove that you have taken the necessary actions by your behaviour and openness are timely, receptive, and appropriate. Provide tours for the community.

Costs of prevention
Depending upon the size of the operations and the number of chemicals actively in use within the facility, it may be prudent to invest in some technologies to assist in managing and monitoring chemical flow through a facility. One of the most economical costs of management is to invest in technologies that are available to assist your firm in properly handling chemicals. Technologies can range from software to hard products. Numerous software packages (ie. Pro-Smart) exist for process safety management. These programs allow management and effective measurement of safety programs on an ongoing basis providing alerts to areas needing improvement and areas needing immediate action. Hazard analysis is key to any existing as well as new process.

Following the accident at Teck Cominco’s Trail lead smelter, the company unveiled new plan for worker protection against potential exposure to thallium.

The new protective measures include:

  • fully sealed clothing to prevent skin exposure;
  • air supplied welding hoods with a 1000 times protection factor against inhalation exposure;
  • a revised work schedule of staggered shifts that will have each welder in the boiler for only 6 hours in a 12-hour shift;
  • decontamination facilities to ensure workers stay clean and do not take contamination from the workplace;
  • daily thallium and arsenic biological tests, as well as weekly tests for lead and cadmium. Tests for mercury will be taken at the beginning and end of the work;
  • additional job site air monitoring;
  • a special joint company, union, contractor safety committee;
  • daily formal audits of safe work procedures by Teck Cominco Safety Coordinators; and,
  • all workers on the job will be given copies of all safe work procedures and Material Safety Data Sheets (MSDS).

Medical authorities indicate that thallium levels in the workers are falling rapidly and that no one is expected to suffer long term health effects.

Yet the incident is a grim reminder of the dangers inherent when working with toxic chemicals.

Teck Cominco’s public relations spokesperson, Richard Fish, wouldn’t estimate how much the accident cost the company in dollars, but he did caution Canadian plant managers about the price of a chemical-related mishap.

"An incident like this carries all sorts of costs over and above the financial concerns." he says. "We’ve had to repair our image among customers, our own employees, contractors and local community." and concern from regulatory authority, lot of implications for the organizations. It had an impact no one would want to experience."

Peter Fretty is a freelance writer based in Michigan. You can reach him at