The first coil was passed through the pickle plant's acid tanks just 39 days after the blaze that forced the evacuation of 80 workers from the Bayview Road mill and the nearby Esso refinery, and cost the company up to $46million in damage, repairs and loss of income.

The company pulled out all stops to bring by road four decommissioned acid tanks from Port Kembla to replace the plastic tanks that fed the May fire and were destroyed.

The operation was expected to take six weeks.

A company spokesman said getting the pickle line operating was "achieved thanks to the tremendous work from hundreds of people at Western Port and the broader BlueScope organisation, our alliance partners and contractors".

"The pickle line is ramping up production across the full product range and our other manufacturing units that have experienced significant idle time during the recovery are resuming production."

The pickle factory, a three-storey building 360metres long, is a vital part of the hot strip and cold rolling mill production chain.

Its acid tanks are used to remove impurities from 25-millimetre thick steel before it is rolled thinner into flat steel products such as Colorbond and Zincalume and for the auto industry.

The restart is good news for the company's 950 employees and about 300 people working for BlueScope contractors. During the fire in May, about 140 CFA volunteers from brigades across the peninsula and south-east used more than a dozen water-pumping tankers and a snorkel to pour water onto the three-storey-high roof, a large section of which was damaged and is being repaired.