Petroleum storage tanks near Sprague Terminal in South Portland. Supporters of proposed statewide testing of tank emissions said current tests aren’t done close enough to the tanks. “Currently, we are unable to say whether the air in South Portland is or is not safe to breathe,” City Manager Scott Morelli said. Derek Davis/Staff Photographer

A legislative committee is developing new rules to more closely monitor hazardous air emissions from petroleum storage tanks – a move opponents say is unnecessary but supporters argue should start sooner than proposed.

The proposed rules were prompted by 2021 legislation that required continuous “fenceline monitoring” of off-gassing from aboveground petroleum storage tanks like those along the South Portland waterfront.

The proposed rules give petroleum companies 15 months from enactment to begin monitoring emissions, but members of the local environmental group Protect South Portland want the deadline to be nine months.

“It won’t take 15 months to get this going,” said Roberta Zuckerman, a group leader. “Why would they not want to prove their tanks are safe?”

More than 20 residents of South Portland, Portland and Cape Elizabeth testified in support of the rules Wednesday before the Environment and Natural Resources Committee, along with representatives of several environmental and health advocacy groups. South Portland has more than 100 large tanks storing gasoline, heating oil and other petroleum products.

Zuckerman said the proposed rules have been strengthened to require continuous testing for benzene and three other volatile organic compounds: ethylbenzene, toluene and xylene. Exposure to the compounds, or VOCs, can cause a variety of health problems, including eye, nose and throat irritation, headaches and loss of coordination, nausea, organ damage, and in some cases cancer, according to health experts.


Protect South Portland also wants the rules to require that the results of fenceline monitoring be released to the public, she said.

Opponents say an air quality testing program launched in 2019 by the Maine Department of Environmental Protection hasn’t detected excessive levels of those compounds. The program takes air samples every six days at several locations across the city.

The DEP started the testing program after the U.S. Environmental Protection Agency filed a lawsuit that revealed an oil storage facility in South Portland operated by Global Partners LP had violated the Clean Air Act for more than a decade. Sprague Energy also was cited for air quality violations at its Fore River tank farm.

With fenceline monitoring, testing equipment would be installed at the edge of tank properties and sample air emissions over two-week periods. Heated tanks would undergo more complex testing twice each year.

The Maine Energy Marketers Association testified Wednesday against fenceline monitoring, saying it’s “a bit too aggressive at this point, as well as premature,” and would be costly to the state. The association represents 300 companies with over 10,000 direct and indirect employees, including gas stations, convenience stores and fuel delivery businesses.

“There isn’t data at this point to support this bill that potentially creates a burden on Maine citizens and businesses,” said Megan Diver, association vice president.


Quincy Hentzel, head of the Portland Regional Chamber of Commerce, said the rules threaten to make Maine an outlier in the region and disadvantage the state’s economy without providing measurable environmental, health and safety benefits.

Hentzel said the DEP’s air monitoring program is one of the most comprehensive in the United States and shows “the air quality in South Portland is in line with other urban areas.”

But supporters of the new rules say the DEP program has been inconclusive, in part because it’s based on weekly air samples taken far from the tanks.

Petroleum storage tanks near Sprague Terminal in South Portland. Derek Davis/Staff Photographer

“Currently, we are unable to say whether the air in South Portland is or is not safe to breathe,” City Manager Scott Morelli said in his testimony. Fenceline monitoring would expand everyone’s understanding of the emissions being released, he said.

Morelli said the DEP program suggests the air in South Portland is “relatively safe,” but the monitoring stations were not placed near the tanks or surrounding residential neighborhoods.

“We do not know the localized emissions from the facilities or the associated health risks in those neighborhoods,” he said.


The Board of Environmental Protection also raised concerns about the proposed monitoring, saying that petroleum companies and DEP staff questioned whether data collected would be meaningful if tanks are near each other and if testing didn’t account for shifts in wind direction.

In a letter to the legislative committee, the board said it supports legislation to reduce or evaluate emissions, but the proposed rules may not provide clear information about a single facility or ambient air quality.

Morelli deflected the board’s concerns, saying that shouldn’t be the reason that fenceline monitoring isn’t installed.

“This data will be vitally important to either help assure the public that our air is safe to breathe, or to take mitigating action to ensure that it is,” he said.

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