RICHMOND -- Chevron will use chrome alloy to replace all the piping in the sections of its Richmond refinery that were damaged in an Aug. 6 fire that hobbled the fuel factory and curtailed its production, the energy giant said in a letter it released Wednesday.

The chrome alloy pipes could address one of the key issues that contributed to the fire. Chevron has notified industry officials that thinning and corrosion in pipes at the refinery may have caused pipe failures ahead of the accident and fire, according to the letter issued by Nigel Hearne, general manager of the Richmond refinery. Hearne sent his letter to the city of Richmond and the Bay Area Air Quality Management District.

The fire knocked out the refinery's crude unit No. 4, which processes and distills crude oil and is deemed to be the heart of the plant. Since the fire, the Chevron refinery has been operating at around 60 percent capacity and has primarily blended gasoline.

"We are optimistic we can complete our planned repairs and be in a position to restart the crude unit by the first quarter of 2013," Hearne wrote in the letter.

San Ramon-based Chevron intends to replace damaged support structures, pressure vessels, tanks and pumps, along with the chrome alloy pipe replacement. The company also intends to repair the cooling tower, motor control center, and fix an array of instruments and electrical systems.

"It was helpful to have the planned repairs laid out in a fairly comprehensive way," said Bill Lindsay, Richmond's city manager. "For us, we will keep evaluating and reviewing the permit applications that are submitted. We hope to be able to do what the City Council wants us to do, which is to process the permits for repairs and rebuilding expeditiously."

City officials also were encouraged about the Chevron plans to replace the pipes that may have corroded with pipes made with chrome alloy.

"It is significant that Chevron is changing the material in their pipe replacement," Lindsay said. "I understand that it is a better material to deal with the conditions that led to the thinning and the accident."

United Steelworkers Local 5, which represents 600 employees at the Chevron refinery, is also following the repair and replacement efforts closely.

"Our main focus is on the safety of the workers, the safety of the environment and the safety of he community," said Mike Smith, a representative for Local 5. "We will be vocal if we think anything is going in the wrong direction."

The refinery has the capacity to handle 244,000 barrels of crude oil a day. Soon after the fire knocked the refinery offline, gasoline prices spiked in the Bay Area. Prices have retreated somewhat since then, however. The refinery's restoration could offer welcome relief for California drivers since the plant is one of the largest refineries in the nation.

The average price of gasoline was $3.94 a gallon on Thursday, which was 2.1 percent above the $3.86 average price in the hours before the early August fire. When Bay Area prices rocketed to a record high average of $4.70 a gallon in early October, those per-gallon prices were about 22 percent higher than the fire.

"We look forward to returning the refinery to full production," Hearne said in his letter.

Contact George Avalos at 925-977-8477. Follow him at twitter.com/george_avalos.