By Marianna Parraga
CARACAS (Reuters) - Workers have restarted two key production units at Venezuela's biggest refinery after an explosion a week ago that killed nearly 50 people, sparked a huge fire and halted operations at the facility, state oil company PDVSA said on Friday.
Firefighters battled for days to put out burning storage tanks. None of the production units were affected, but were temporarily taken off line at the 645,000 barrel per day Amuay refinery, which is part of the second-biggest refinery complex in the world.
"Operational activities have resumed safely and gradually," PDVSA said in a statement, adding that two crude distillation units with a combined capacity of 160,000 bpd were now running, and that a third was due to restart soon.
It said other smaller processing units, including ones that make naphtha and kerosene and have a combined capacity of about 58,000 bpd, were also operating normally.
The authorities are investigating what may have caused a gas leak that led to Saturday's pre-dawn blast. In addition to those killed, the explosion wrecked about 200 nearby homes.
The accident was the global oil industry's most deadly in recent years, nearing the toll of a fire that killed 56 people in 1997 at India's Visakhapatnam refinery.
Experts say PDVSA might have to run Amuay's restart process more slowly than normal following the blast, while workers continue to clear debris, cool the area affected by the blaze and check the system for any more leaks or other problems.
The water, power and steam supplies to the Amuay refinery, which by itself is the world's fourth biggest, were not interrupted by the disaster, however, which should help save some time.
One oil industry source said that the damage to the refinery could end up costing about $3 billion, but that PDVSA has yet to choose a company to carry out an audit.
As operations begin to return to normal, PDVSA said two tankers were loaded on Friday with a total of 510,000 barrels of oil products for the domestic market from docks at Amuay and the neighboring Cardon refinery.
Four more tankers were waiting to be loaded, the company said, one bound for an oil storage terminal in the Caribbean and another destined for Africa.
(Writing by Daniel Wallis; editing by Carol Bishopric)