Safety Notice #5: Subway Air Quality Update

The following information is provided as an update to the Safety Notice #4 – Subway Air Quality Update – issued on September 21, 2017.

From the Safety and Environment Department

The following information is provided as an update to the Safety Notice #4 – Subway Air Quality Update – issued on September 21, 2017.

Background - Health Canada Study 
On April 25, 2017, a study by Health Canada on TTC air quality was published in a scientific, peer-reviewed academic journal. The study was conducted to compare dust exposures between major transit properties in Canada to help guide transportation planners in Canada to improve air quality for commuters. The purpose was to gather information about dust levels, not to draw conclusions about the impact of the dust levels on health. The study confirmed previous internal assessments that found that the dust is primarily iron from steel wheels and rails, and that it is dustier in an enclosed subway tunnel than outside.

TTC Subway Air Quality Study
The TTC initiated a subway air quality study in 2017 – this study is currently underway. An Advisory Working Group comprised of Union Safety Officers from the ATU Local 113, CUPE Local 2 and CUPE Local 5089 and TTC’s Occupational Hygiene and Environment Section met to discuss the specific scope of the study.

The purposes of the Subway Air Quality Study are to:

  • Provide current information on the air quality in the underground portions of the subway during revenue service;
  • Determine employee exposures to airborne contaminants to ensure safety at work;
  • Evaluate the effectiveness of current controls;
  • Make recommendations regarding both compliance with the Occupational Health and Safety Act (OHSA) and opportunities for general improvement.

Tier One – Air Sampling Results
The first round of air sampling has been completed – this focussed on work positions from the various bargaining units noted, with duties requiring the incumbents to generally spend the greatest amount of time in the subway during revenue service, including:

  • Maintenance Mechanics;
  • Signals Technicians;
  • Line Mechanics;
  • Escalator Mechanics;
  • Sunset Corridor Services;
  • Special Constables;
  • Fare Enforcement Officers;
  • Track Patrollers;
  • Subway Operators (Line 1, 2 and 4);
  • End Terminal Cleaners;
  • Subway Janitors;
  • Traffic Checkers.

None of the 63 sample sets collected to date (each analyzed for approximately 29 separate contaminants) exceeded the occupational exposure limits specified in Regulation 833 – Control of Exposure to Biological or Chemical Agents, made under the Occupational Health and Safety Act. All exposures were well below the occupational limits.

Based on the interim sampling results, the subway air quality continues to be deemed safe for employees and is not expected to affect the health of employees in the work positions assessed who do not have pre-existing serious respiratory conditions.

Based on the results of the air sampling obtained to date, the use of respiratory protection during the work shifts studied is not required. Should an employee have a pre-existing serious respiratory condition, the TTC continues to offer accommodation on a case-by-case basis as required.

Next Steps
Formal reports will be issued to affected work locations. Further sampling will be conducted throughout 2018, followed by final reports.

If you have any questions, please contact Stephanie Fortin at 416-393-3262.

John O’Grady
Chief Safety Officer
Safety & Environment Department
April 6, 2018

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