The Environmental Protection Agency has long maintained that a new proposed utility rule to reduce mercury and other emissions won’t affect the reliability of the nation’s power grid — but Congressional and industry investigators have found that an early draft of the rule that circulated within the administration included a section that acknowledged the rule might negatively impact reliability, the WSJ reports.

It’s obvious to those who’ve examined the rule at any length that it’s designed to close coal-fired power plants, and, given the prevalence of such plants, it’s easy to infer that a rule to eliminate them would risk blackouts — but supporters of the rule brand anybody who opposes it an abettor of pollution and an accomplice of the industry.

As the WSJ explains, this newly discovered admission by the EPA itself that blackouts are a possible consequence of the rule gives the lie to that characterization:

In a “What are the energy impacts?” section, the EPA concedes that it “is aware that concerns have been expressed by some, even in advance of this proposed rule, that this regulation may detrimentally impact the reliability of the electric grid.” The agency admits that what it calls “sources integral to reliable operation” may be forced to shut down—those would be the coal-fired plants the EPA is targeting—and that these retirements “could result in localized reliability problems.” The EPA insists that it knows how to balance “both clean air and electric reliability,” but all along in public it has denied that reliability is in any way at risk. …

But here’s the kicker: This reliability section was gone when the EPA released its utility rule proposal in May 2011. Why did it vanish? Where did it go?

This matters because the draft report contradicts EPA leaders who have publicly portrayed anyone worried about reliability as an industry shill. More importantly, as a technical and legal matter, issues that are excluded from the Federal Register mean that the public is denied the opportunity to meaningfully comment on them.

EPA Administrator Lisa Jackson clearly doesn’t want anyone to comment on the reliability issue — not even the EPA. Not only did the agency scrub the reliability section from the proposed rule, but it has also given the White House regulatory office insufficient time to examine the rule, which the EPA plans to finalize by mid-December. The EPA has also repeatedly ignored letters from Sens. Jim Inhofe (R-Okla.) and Lisa Murkowski (R-Alaska) that ask whether the new regulation will jeopardize grid dependability.

Undaunted, Inhofe and Murkowski have tried yet again, sending a letter to Jackson to ask why the EPA eliminated the reliability section from the rule and also to request the EPA not impair electric reliability and affordability. All bets are against a reply from Jackson.

This rule is one of the most expensive ever proposed by the EPA: According to some estimates, it will cost $184 billion and up to 1.4 million jobs. Coal might be “dirty,” but, at present, the U.S. relies on it heavily. Eliminating it will increase energy costs at a time when the nation just can’t afford it. At least 25 state attorneys general have begged the EPA to delay this rule by at least a year. The EPA would do neither itself nor the energy industry any harm by heeding that request.

Incidentally, this story also underscores the need to ensure congressional oversight of regulations. The REINS Act is the best bill on the table to do just that.

Update: This story originally mistakenly stated the EPA plans to finalize the rule by mid-September instead of mid-December. The post has been corrected above.