It probably would not have taken an ethnic slur to get Richard Allan fired. But a racially charged comment, emailed via government computer from Allan to his wife, made it convenient for Gov. Tom Corbett to ditch his Department of Conservation and Natural Resources secretary.

Allan resigned Thursday at Corbett’s request. No official reason was disclosed, but media reports alluded to the offending email, which reportedly was seen by a workmate of Allan’s wife.

Allan, 60, has maintained a low profile since he joined the Corbett administration shortly after the governor took office in 2011, leaving a career in the scrap metal industry to do so.

The DCNR chief’s days already were numbered, and a debate over natural gas drilling was a deciding factor.

While drilling for oil and gas on state forest land dates back at least to the 1960s, new technology has enabled the harvest of previously unprofitable gas deposits and reinvigorated the industry.

Marcellus Shale, a geologic formation found across Pennsylvania, holds gas that now can be harvested using new techniques to fracture or “frack” the rock and release the gas. However, fracking uses thousands of gallons of water and a mix of potent chemicals. Experts debate the safety of fracking and the risk of contamination of water wells and surface water.

DCNR officials under Allan’s leadership estimated some 3,800 deep Marcellus gas wells will be drilled on leased tracts of state forest by 2018.

But public opposition had been growing against Allan over potential drilling, particularly in the 100,000-acre Loyalsock State Forest in north-central Pennsylvania. Some 500 people attended a public hearing last week, with opponents arguing the land is a public trust about to be exploited without public consent. Allan has been accused of advancing the drillers’ agenda without responding adequately to environmental concerns.

Allan’s deputy secretary, Ellen Ferretti, was appointed Thursday as acting DCNR secretary. Ferretti is a former president of the northeast regional office of the Pennsylvania Environmental Council, a group that promotes cooperation between business and environmentalists and environmental stewardship by business. As DCNR’s deputy secretary for parks and forestry, she was tasked with developing specific policy dealing with Marcellus shale drilling on public lands.

Environmental groups have said they hope Allan’s ouster might translate into a shift in Corbett’s approach to drilling. One called the Loyalsock debate a defining issue for Corbett. It well may be.

New fracking technology that has demonstrated its effectiveness in harvesting natural gas must also demonstrate its safety to the state lands. It’s Ferretti’s job now to determine whether this objective is attainable.