* Unconfirmed reports of an explosion -county official
* Fire put out by refinery personnel
(Recasts, adds details from Chevron statement)
Nov 15 (Reuters) - A Chevron Corp worker was killed on Friday after a fire broke out at a cracking unit at the major U.S. oil company's 330,000 barrel per day Pascagoula, Mississippi refinery in the early morning hours.
Plant emergency teams responded to the fire, which started at 2 a.m. CST (0800 GMT), and have secured the site, Chevron said in a statement. Earl Etheridge, director of Jackson County Emergency Services, said the fire was extinguished.
Chevron said the fire broke out at a furnace at a gasoline-making unit known as the "Cracking II area."
The refinery appeared to have been going through some maintenance work before the fire, according to energy intelligence group Genscape, which reported on Thursday that a unit had shut down and then began restarting with another unit.
Genscape, which monitors activities at refineries by camera, said a 55,000 bpd catalytic reformer, which modifies naphtha into high octane gasoline blending components, had shut down early in the morning and by the afternoon had begun to ramp up together with a 29,000 bpd hydrocracker, which uses hydrogen to break down molecules into other refined products.
Chevron did not reply to a request for comment on the Genscape reports.
The Pascagoula refinery, where operations began in 1963, is the largest of three refineries operating in the state.
The plant can process and treat low-grade heavier, sour, foreign crude oil. It produces about 130,000 bpd of motor gasoline, 50,000 bpd of jet fuel and 68,000 bpd of diesel fuel, according to Chevron's website.
(Reporting by NR Sethuraman in Bangalore; Sabina Zawadzki, Scott DiSavino, and Matthew Robinson in New York; Editing by Dale Hudson, Lisa Von Ahn and Chris Reese)