Trail testing system a failure

Vancouver — Newly formed mining giant Teck Cominco (TEK-T) has determined that a failure in its testing methodology resulted in 65 workers at its Trail lead-zinc smelter in B.C. being contaminated with thallium, a highly toxic metal linked to nerve damage.

The contamination was revealed on Aug. 23. Biological monitoring showed that the contract employees had varying degrees of elevated thallium levels. Teck Cominco immediately suspended work in the area.

An internal investigation has revealed that the contamination occurred because of deficiencies in the procedures that determined the hazards of the project.

Prior to the commencement of work, Teck Cominco tested the “boiler dust” for contamination. The results showed low levels of Thalium — only 0.58%.

However, the company says it should have tested the actual “boiler scale” (material the workers were removing inside the plant boiler). Samples of this material were tested on July 10 in efforts to improve the furnace operation. They showed extremely high levels of thallium — up to 19%.

This information was not taken into account when the hazard levels at the work site were determined.

“If, as part of the hazard assessment, we had assayed the material encountered by workers, we would have immediately recognized the high thallium in the system and the need for higher levels of worker protective equipment,” says David Thompson, Teck Cominco’s CEO.

Based on the contamination, the company is instituting a series of new procedures aimed at preventing a similar incident. These include:

• Determination of hazards through assessments of samples taken from dust and scale in the furnace;
• The use of the highest level of protective equipment, together with enhanced hygiene and decontamination procedures; and
• The employment of international experts to help conduct an extensive audit of procedures and provide recommendations for further improvements to raise plant health and safety practices to the highest possible standard.

The contract workers were carrying out maintenance work on the furnace area of the currently idled smelting facility and began to complain of flu-like symptoms — chills, sore muscles and cold sweats.

During the month-long job, they twice exercised their rights under the Workers Compensation Board’s (WCB) rules to stop work. Both times, the WCB found that the work site was safe. Later, however, tests showed traces of thallium (a chemical byproduct of smelting) in their urine.

The levels of contamination were higher than the “concern level”, prompting the job site to be shut down. The affected workers were wearing personal protective equipment consistent with WCB guidelines for exposure in this type of work.

High-level exposure to thalium can cause nerve problems, such as numbness in fingers and toes. It is potentially fatal.

Since 1935, nearly 800 people have been diagnosed with thallium poisoning. Some 50 of them died.

Teck Cominco is offering medical help to the afflicted workers.