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Toronto hi-rise put on hold while workers debate
Total Dust Control
By Robert Horowitz (1995)Toxic dust from synthetic mineral spray coatings caused 190 Toronto construction workers to walk off their job in May (1995), temporarily halting fabrication of an $80 million, 36-story office tower.
According to an article in Occupational Health and Safety-Canada magazine, at least 110 workers on the site of the massive Eaton Centre were suffering from nosebleeds, coughing, shortness of breath, skin and eye irritation and other "cold-like" and asthma-like symptoms which lasted for months. Workers felt strongly that the ailments were related to a mineral fiber fire retardant which was being sprayed on the structure's steel beams, and after fruitless conversations with management, refused to work.
As dust levels at the work-site apparently were well within Canada's occupational exposure limits, occupational specialists were left wondering what went wrong. Two such specialists, Tom Robinson and Gordon Atherly, surmised in the article that too much emphasis is being placed on numbers, such as threshold limit values for workplace exposure, and not enough emphasis was on common sense and reasonable approaches to ensure worker health.
"It's not that number-based systems like TLVs, toxicology and air sampling have failed us. On the contrary, they have contributed greatly to improvements in the workplace environment," wrote the two in OH&S Canada. "But they are not the only technique for assessing risk. And they are not appropriate for the many situations where information on health effects is incomplete, where TLVs are under discussion, where time-weighted averages are not scientifically valid or where short-term exposure patterns frustrate traditional air sampling techniques."
The writers' discuss how MMMF mixes with other substances at construction sites to form a fiber/particulate brew for which individual exposure limits cannot properly account. The authors state occupational asthma "can be triggered by workplace dust levels much lower than accepted limits."
"Total Dust Control," is the term Robinson and Atherly give to a new system for worker health protection, which they describe as a "win-win" situation for worker and employer alike. Total dust control (TDC) focuses on the sources of airborne contaminants, work practices which create dust, and the environment in which the worker and potentially harmful substances interact. Management and labor need only move beyond the numbers game and do what is reasonable to protect workers. The sticking point, they concede, is: who decides what is a reasonable precaution?
Consider this list:
- adequate ventilation in any area to receive sprayed insulation during and for 24 hours after application,
- temporary enclosures to prevent spray from contaminating the work environment,
- protect tools and work surfaces from overspray,
- delay spraying coating until all clips, hangers and hardware are affixed to beamwork,
- mix each batch of spray separately, clean mixer after each batch, do not use lumpy or caked batches of spray
- water tamping to product a smooth surface, then seal and cure.
