The International Brotherhood of Electrical Workers is the latest to chime in as a critic of the planned merger between Duke Energy and Progress energy. The labor union wants assurances that the companies keep their promise not to lay off any linemen, technicians or field workers as part of their consolidation.

The IBEW was one of a number of groups that filed comments late Thursday to meet the deadline of the N.C. Utilities Commission. The commission is set to hold public hearings in Raleigh in two weeks on the corporate merger that would create the nation's largest electric utility.

Raleigh-based Progress said it plans to eliminate 700 to 1,000 positions in Raleigh, erasing up to half its downtown workforce as the corporate headquarters is consolidated in Charlotte. Progress and Charlotte-based Duke have said they don't expect the job cuts to affect workers in the field and in power plants.

"The companies' nebulous promise to avoid involuntary layoffs 'to the maximum extent possible' is insufficient," the IBEW wrote in its filing.