Lawrence Livermore Laboratory reached an agreement with labor organizers Thursday recognizing a bargaining unit that includes 170 skilled crafts workers such as plumbers and mechanics.

In return, the Society of Professionals, Scientists and Engineers, which led the unionization campaign, agreed to drop two unfair labor practice charges filed with the National Labor Relations Board and one internal grievance.

"We're jubilant," said lab computer scientist Jim Wolford, a leader of the organizing drive. "We were looking at a rather protracted struggle."

Just before an Oct. 1 change in lab management from the University of California to Lawrence Livermore National Security LLC, the California Public Employment Relations Board approved the skilled crafts unit.

But the new manager refused to recognize it and sought to move the matter to the National Labor Relations Board, which oversees labor issues at private companies.

The NLRB requires a one-day election for employees to choose whether to accept the union, usually a more difficult hurdle than the signature collection the state permits.

In response, organizers filed the unfair labor practice charge with the NLRB.

Reach Betsy Mason at 925-952-2056 or bmason@bayareanewsgroup.com.