By Maria Rocha-Buschel
The MTA released a report last Friday afternoon on the dust levels in L stations affected by the tunnel work during the first weekend of the slowdown, concluding that the amount of dust in the air of was “well below” the accepted standard.
The report measured dust concentrations in the public spaces at the Bedford and First Avenue stations before, during and after the work was being done, from noon on Friday, April 26 to noon on Monday, April 29.
The MTA is using a standard that was established by the American Council of Government Industrial Hygienists for people who are potentially exposed to these levels for eight hours a day over a 45-year career.
The transit agency noted in the report that there isn’t an established standard exposure limit for the (usually short) periods that straphangers would typically pass through subway stations so the agency is using the long-term chronic standard as a health-protective benchmark. Dust levels were found to be below the standard of 3,000 micrograms per cubic meter of air (µg/m3).
The transit agency is also monitoring the public areas of the station for the presence of respirable crystalline silica in dust. The Occupational Safety and Health Administration has established a long-term benchmark of 50 µg/m3 for workers that are exposed to silica for eight hours a day over the course of a 45-year career, and the MTA worked with public health experts to establish a short-term exposure benchmark, finding that limiting exposure to 1,000 to 3,000 µg/m3 would be health-protective for the time that commuters are usually on a subway platform.
The report noted that silica can’t be measured directly but requires sampling of dust, and based on dust concentrations of 600 µg/m3 observed in the stations, the concentrations of silica would be at or below the long-term standard.
Based on 28 samples taken from two locations at each of the stations, there was not enough silica present in 25 of the samples to return a result. In the three samples where concentrations of silica could be measured, the values were between 8 and 12 µg/m3.
Councilmember Keith Powers and Assemblymember Harvey Epstein were both cautiously optimistic about the results of the testing, but noted that it’s still early in the project.
Epstein said that residents might still be concerned despite the results of this testing but he hopes that as the construction progresses, the MTA will be able to address those issues as they arise and was hopeful about the agency’s willingness to be forthcoming with the data.
“It does seem like an adequate first week but (the report) doesn’t necessarily alleviate concerns about dust,” he said. “They have been really responsive about transparency and data and that’s been helpful. As it moves on it’s going to get more complicated. I’m hopeful that they’ve been so responsive already that if the levels do rise, they’ll be able to address it.”
Powers said that since he was optimistic the MTA will continue to test the dust levels since he got an opportunity to see the equipment that monitors the tunnel.
“We’re happy that they listened to our office and we have to keep monitoring it along the way as construction continues,” he said. “We are going to get regular reports and see if anything changes but it’s good they’re up and running now.”