Two of America’s best-known green investors are reassessing their stakes in global insurance broker Arthur J. Gallagher & Co after a Reuters investigation into the company’s lucrative side-business in “clean coal”.


A.J. Gallagher (AJG.N) has invested in 34 facilities producing so-called refined coal, which is chemically treated to make it burn cleaner and heavily subsidized by the U.S. government. The firm also holds a 46.5 percent stake in Chem-Mod LLC, which provides the chemicals used to produce the fuel.


A.J. Gallagher has accumulated about $850 million worth of U.S. government tax credits from the business. But many utilities burning the coal have pumped out more smog, not less, over the past decade, and the chemicals have contributed to elevated carcinogens in downstream drinking water supplied to more than 1 million people, according to the Reuters Special Report.


Now, the Green Century Funds and Calvert Funds – which include A.J. Gallagher in their portfolios based on its record as an insurance firm, not a coal supplier – said they will review the company’s green credentials. Green Century and Calvert are two of nation’s leading money managers focused on corporate environmental, social and governance matters.


The idea behind the strategy is to help investors sidestep companies whose activities they find objectionable, such as polluting the environment.


“In light of this new information, we certainly will … press the company to stop profiting from schemes devised by the fossil fuel industry to the detriment of U.S. citizens and taxpayers,” Green Century said in a statement, calling clean coal “a myth”.


A.J. Gallagher is one of about 360 companies in the $250 million Green Century Equity Fund GECQX.O, which advertises itself as “100% percent fossil fuel free.”


The fund, which held 4,394 A.J. Gallagher shares at the end of October, is passively managed and invests in the companies that are in an index run by MSCI Inc.MSCI declined to comment for this story.


Calvert Research and Management, a unit of Eaton Vance Corp, said it has contacted A.J. Gallagher as part of a reassessment of the company’s ESG performance. A.J. Gallagher is a holding in the $1.3 billion Calvert U.S. Large Cap Core Responsible Index Fund (CISIX.O).


“In response to this new information, we have contacted the company and will consider this information in our assessment of ESG performance,” Calvert said in a statement, referring to the Reuters reporting.