The cleanup of the General Chemical site in Framingham was suspended for about 30 minutes Monday after monitoring of the air quality at the site on the morning of the first day of the operation showed pollutants that exceeded screening levels established by state environmental officials.
Representatives of the state Department of Environmental Protection ordered workers to make adjustments to lower the risk of potential contaminants in the air and the cleanup resumed, said DEP spokesman Ed Coletta.
Local residents and businesses were not in any danger on Monday, Coletta said, since the screening levels are below what would pose a threat to public health.
"The screening level is an abundance of caution, and is no where near any kind of health risk action level," he said. "But the test said there might be an issue, so they shut it down to figure it out."
Coletta said vapors escaped from the first tank being cleaned Monday when air was being blown into the tank to provide sufficient oxygen for the workers in there.
Workers stopped the job for just over 30 minutes and changed the tank ventilation approach by extracting air from the bottom of the tank to allow fresh natural air to enter at the top, and filtering the air subsequently escaping the tank.
"A lot of chemical facilities handle organic compounds, so if you're cleaning that stuff out, the issue is if any of those vapors is in the ambient air," he said. "The monitors catch that. Even though the level of exceeding was very, very low, we wanted to take an abundance of caution."
The cleanup comes after the New Jersey-based General Chemical Corp. filed a notice of closure for their 2-acre facility on Leland Street in Framingham on March 1, after years of complaints from Framingham residents and officials about potential health hazards in the vicinity, including the nearby Woodrow Wilson Elementary School.
The cleanup in South Framingham is scheduled to continue until up to Aug. 15 Monday through Saturday, 8 a.m. through 10 p.m. Workers can only operate noisy machinery until 6 p.m. each day, Coletta said.
General Chemical is required to pay for all costs associated with cleanup, and have placed downwind air emissions tests throughout the site to look for dangerous levels of air pollutants.
MassDEP workers will also remain on the General Chemical site throughout the duration of the cleaning period. They will have a mobile laboratory where state officials can conduct their own real-time tests, Coletta said.
Coletta said the state advises residents and businesses in the local area to keep their windows closed, to keep away from the General Chemical site and property lines, and to avoid Woodrow Wilson Elementary and its playground.
An initial pilot test conducted by General Chemical and overseen by DEP in late June showed the level of air pollution did not exceed any health limits, giving the green light for the full-fledged cleanup, department officials said previously.
Jaclyn Reiss can be reached at firstname.lastname@example.org