Say this for John Quigley, until a few days ago the state of Pennsylvania’s top environmental officer. With a profanity-laced email that played a role in his resignation he put the dangers of hydraulic fracturing front and center in the public consciousness. Mr. Quigley had backed tough new updates in state rules governing drilling for natural gas. But after legislators voted them down, he blistered environmentalists for failing to support the cause.

“Where the (expletive) were you people yesterday?” he wrote in an email on April 13. “The House and Senate hold Russian show trials on vital environmental issues, and there’s no pushback at all from the environmental community? Nobody bothering to insert themselves in the news cycle?”

A few more expletives later and Gov. Tom Wolf reportedly began questioning whether Mr. Quigley could any longer be effective in his job.

His voice could be missed. Natural gas is big business in Pennsylvania, which sits on top of the Marcellus Shale, whose rich deposits have brought jobs and revenue to the state. More than 9,000 oil and gas wells have been drilled using hydraulic fracturing in Pennsylvania since 2005, the most in any state on the Eastern Seaboard.

The shale bonanza has also brought environmental headaches and raised concerns about whether the companies have disadvantaged poor people by drilling wells in low-income areas and exposing them to dust and traffic as well as air and water pollution.

In a letter last month, the Center for Coalfield Justice, the Pennsylvania chapter of the Sierra Club and the Clean Air Council asked the state’s Office of Environmental Justice to give the public more say in the permitting of wells. The groups believe the industry may be choosing drilling sites that disproportionately affect low-income and minority residents.

Pennsylvania is not the only state where fracking has raised such concerns. In California’s Kern County, Latino and African-American residents are disproportionately likely to live in high-pollution areas near oil and gas wells. Environmental groups are fighting a county ordinance that could allow thousands of new wells without full environmental review. In the Eagle Ford shale field of southern Texas, a recent study found that sites for the disposal of fracking wastewater were disproportionately located in areas with high percentages of poor and minority residents. Many states have laws or policies that are supposed to ensure equal protection from environmental and health hazards, but not all are reliably enforced. And some states are striking down local laws passed by communities that don’t want fracking.

Fracking Houses