CALTEX'S Kurnell refinery was in damage control after Monday's heavy downpour, which caused a release of oily water into Botany Bay.
A Caltex spokeswoman said the oil release was contained and dispersed on Tuesday morning.
"Caltex, along with Sydney Ports Corporation, have inspected both the north and south side of Botany Bay by boat and also by foot along the beachfront," she said.
"Booms will remain in place on the south side of the bay for another tide change as a precaution only.
"No odour or sheen was detected and all appears to now be clear."
However, a Kurnell resident, who wished to remain anonymous, said he noticed an overpowering smell of petrol at noon on Monday.
"I live about 150 metres away from the refinery and I could smell a very prominent odour of petrol," he said. "It's quite concerning to me that nothing was said to the residents, there were no signs put up to stay out of the water until it got tested and it's all really hush-hush."
Recreational Fishing Alliance chairman Malcolm Poole said anglers were concerned about the immediate and long-term effects of the oil spill.
"The public were gathering, watching the wind drift oil spill wash-up on the local beaches, the white sand being covered with an increasing oily scum and sludge," he said.
"No health or safety warnings were posted at local boat ramps, in the bay or . . . beaches by those in control of the oil spill."
Another alliance member told radio station 2UE on Tuesday that it was the biggest spill he had seen in 30 years of fishing in and around Botany Bay.
Nature Conservation Council of NSW chief executive Pepe Clarke said Caltex breached the pollution licence at the site more than 140 times since 2000.
"This company is a repeat offender, which appears to treat pollution penalties as a cost of doing business," he said.
"Blaming the weather for the oil spill is a weak excuse . . . The pollution control systems at the refinery should be built to cope with heavy rain."
He called on the EPA to take "firm action to ensure the company upgrades its pollution-control systems to reduce risks to public safety and the environment".
A Sydney Ports Corporation spokesman said it, the EPA and other environment bodies found no evidence of environmental damage or harm to wildlife on Tuesday.