(Updates with news)
TOKYO, March 1 (Reuters) - Japanese oil refiner TonenGeneral Sekiyu KK said several workers were injured when a fire broke out on Saturday in the residue hydrocracking unit of its Kawasaki plant near Tokyo, but that other refining units were operating normally.
The fire originated from the reactor of the 31,000 barrel per day hydrocracking unit during cleaning work at around 0440 GMT, the company said in a statement.
The unit, which processes low-priced heavy oil into lighter products such as gasoline, has been shut since early February for maintenance, a company spokesman said.
The company has plans to raise the capacity of the unit to 34,500 bpd this month to meet government rules on improving efficiency.
TonenGeneral said the fire had almost been brought under control by pumping nitrogen into the unit. Six workers were treated in hospital and one of them was been admitted.
Local officials said the fire had not spread to the surrounding facilities.
TonenGeneral said it was continuing normal operations at crude distillation and other secondary units at the Kawasaki plant, which has a capacity of 335,000 barrels per day, and that there had been no impact to shipments from either its marine or truck terminals.
However, it was not yet clear what had caused the fire, how much damage had been done to the hydrocracking unit, or when it would resume operations, a company spokesman said. (Reporting by Osamu Tsukimori; Editing by Kevin Liffey)