The Five Islands Rd company has started the Major Projects process rolling for a new liquid waste processing facility, which would process and treat up to 6,500 tonnes of liquid waste a year

Hydromet extracts valuable compounds such as lead, tin, zinc and copper from waste, for reuse. It processes about 36,000 tonnes of lead batteries each year.

Hydromet said the proposed liquid waste plant would produce an 80 per cent reduction in solid waste disposed to landfill, compared to conventional treatment processes

Read more: NSW Govt slammed over 'egregious' Hydromet failures

The company's planning application says it has "a number of" environmental management plans to deal with any spillage or environmental impact.

Major questions were raised about the level of government oversight of the operation after a District Court judge's scathing comments last month.

Hydromet and a company director were convicted and fined over a 2017 incident in which the two workers were badly burned after they were sprayed with acid while trying to fix a leaking hose.

"Their injuries occurred because of the failure by Hydromet to eliminate or minimise risks arising from the processing of hazardous chemicals," Justice David Russell ruled.

He condemned the level of government oversight.

"I do not understand why a business which handles extremely hazardous chemicals is given a licence and is then in effect left to police itself," he said.

"The facts in this case demonstrate that Hydromet could not be trusted to comply with its obligations.

"Hydromet was guilty over a lengthy period of a litany of failures to fulfil its statutory obligations. Why did workers have to be seriously injured before that came to the notice of the authorities?"

Hydromet was also fined $15,000 in 2018 after an Environment Protection Authority inspection found numerous breaches of its licence conditions regarding chemical storage.