A panel headed by D.C. Council member Yvette Alexander killed the controversial appointment. (Katherine Frey/THE WASHINGTON POST)

Elizabeth A. Noel served 18 years as the people’s counsel, a government attorney representing city residents in rate cases and other utility matters, before Mayor Vincent C. Gray (D) nominated her last year to join the commission she had often argued before.

The nomination turned into a bruising battle between Pepco and allied business interests, who questioned Noel’s impartiality given her previous work, and labor unions and consumer advocates, who have accused the commission of being in thrall to the utilities they regulate.

The business lobby’s concerns were reflected in comments made ahead of the Committee on Public Services and Consumer Affairs vote Thursday. Yvette M. Alexander (D-Ward 7), the panel’s chairwoman, said she was concerned that Noel, by one estimate, would have to recuse herself from perhaps 60 percent of the current cases before the commission.

Alexander was joined in opposition by Muriel Bowser (D-Ward 4) and Phil Mendelson (D-At Large), who both were critical of Noel’s testimony during an Oct. 11 hearing on the nomination.

But Mary M. Cheh (D-Ward 3), who was joined by Jim Graham (D-Ward 1) in supporting Noel, said it is common for lawyers serving as zealous advocates to take on new jobs, such as judgeships, that require more evenhanded deliberation.

“What’s really behind this is Pepco. Pepco wants another puppet on the commission,” she said. “Betty Noel is nobody’s puppet, and Pepco knows it.”

Pedro Ribeiro, a spokesman for Gray, said the administration is “assessing” whether it has other options in pursuing Noel’s appointment. “Today’s vote has denied District residents the watchdog they need and deserve,” he said.