UPDATE 1-Chevron to appeal to resume Calif. refinery work

(Adds quotes, environmental group reaction, details)

HOUSTON, July 9 (Reuters) - Chevron Corp (CVX.N) plans to appeal a California judge's ruling that halted a $1 billion project to build a hydrogen plant at its San Francisco Bay refinery in Richmond, California, a company spokesman said on Thursday.

Chevron will not ask for a stay of the order, which brought the expansion project to an abrupt halt last week, forcing the layoff of 900 out of 1,000 construction workers, said Chevron spokesman Brent Tippen.

"We believe the court's decision was erroneous with regard to the environmental impact report," Tippen said.

Contra Costa County Superior Court Judge Barbara Zuniga ruled in a July 2 decision that the environmental impact report filed to obtain construction permits for the new hydrogen plant failed to depict how pollution from the refinery would be changed after the project was complete and provide a greenhouse gas mitigation plan as required by California law.

California environmentalists had fought the expansion's approval by the Richmond City Council, citing flaws in the environmental report required by state law. They filed the lawsuit after the Council approved the project and work began in November.

"This is not a surprise," said Torm Nompraseurt of the Asian Pacific Environment Network, which opposed Chevron.

"Chevron has all the money in the world to hire all the legal help they need," Nompraseurt said. "What Chevron needs to give the community is a good EIR and disclose all the information to the community." (Reporting by Erwin Seba; Editing by Marguerita Choy)