CHARLESTON, W.Va. -- Sen. Jay Rockefeller, D-W.Va., wrote to the president of Century Aluminum this week, urging him to restore health benefits to the retired employees who worked at its aluminum plant in Jackson County, as well as their spouses.Century closed its plant in Ravenswood on Feb. 15, 2009, laying off 651 workers. In July 2011, Century's retirees lost all company health benefits they believed they had been promised under union contracts negotiated by the United Steelworkers union.The retired Century workers and their spouses reached a compromise agreement with Century on March 15 about their health benefits, as one pre-condition to opening the plant.But when -- or if -- the plant will reopen remains unclear. Century Aluminum and Appalachian Power were unable to agree on a special rate for electricity to the plant last month, one of the conditions for reopening the plant.On Tuesday, Rockefeller sent a letter to Michael E. Bless, president and CEO of Century Aluminum, asking him to do everything he can to reinstate health-care benefits as quickly as possible.Many former employees and retirees face difficult financial choices about whether they can afford medical treatment, Rockefeller said.In the letter to Bless -- who plans to visit West Virginia sometime in July -- Rockefeller praised Bless for his efforts to reopen the plant and reinstate health benefits."I appreciate your efforts as well as the good working relationship we have developed over the past several months," he wrote.However, Rockefeller expressed concerns that the plant apparently will not reopen in August, as originally planned."Unfortunately, it now appears that one of the conditions -- securing a new power rate -- may not occur for several months and must be followed by a new contact with the employees' labor union [the United Steelworkers of America] and the federal court's approval of a settlement agreement related to the retirees' lawsuit against the company."If Century reopens the plant, 450 jobs are likely to be restored almost immediately, company and local officials have said. Another 200 jobs could be added later.Rockefeller's letter to Bless added, "These outstanding hurdles will undoubtedly delay the reopening of the plant and the reinstatement of retiree health-care benefits for months, which forces retirees to put off needed health-care [actions]."Rockefeller asked Bless to "do everything you can do to restart the Ravenswood smelter and begin making payments into the retirees' [benefits trust fund] as soon as possible."Reach Paul J. Nyden at firstname.lastname@example.org or 304-348-5164.