The state's coal seam gas industry is under a cloud after separate matters involving the safety of operations at Narrabri in northern NSW and near Sydney.
The Land and Environment Court on Monday ordered Santos to make public water-monitoring data after legal action by farmers in the Pilliga Forest concerned about possible contamination to bores from CSG drilling.
"It's a complete win," said Sue Higginson, principal solicitor of the NSW Environmental Defenders Office, adding Santos had refused to release information that was "in the interests of the entire community" in Narrabri.
Santos has until the end of October to disclose all test results from sampling of bores on the affected property, owned by Tony Pickard, and the expert advice it received. Water from two bores became undrinkable in 2012.
The company must also release all water-quality testing of groundwater samples it has taken from stock and domestic bores within four kilometres of its CSG drilling sites, as well as all documents related to leaks, spills or overflows from its wastewater storage activities at the Dewhurst CSG site.
"This case highlights the problems of a largely self-regulatory system which relies on CSG companies doing their own water monitoring and reporting, and does not require this information to be made public," Ms Higginson said.
A spokeswoman for Santos said the company would meet the deadline for data release.
"Santos remains confident that there is no connection between our operations and the bacteria identified in Mr Pickard's bore," she said. "At all times, Santos has acted in good faith with the information requested by the EDO."
Meanwhile, the Environment Protection Authority said it was investigating the release of gas from AGL's CSG site at Camden in Sydney's south-west on Sunday night.
Residents reported a loud bang and hissing sounds from about 7.30 pm, prompting three NSW Fire & Rescue crews to attend.
AGL said the sound emanated from a safety release valve at one of the wells at its Spring Farm site and "a small amount of natural gas" had escaped. "At no time were any local residents at risk," an AGL spokeswoman said.
The EPA on Monday sent an officer to inspect the well, conduct monitoring for methane emissions and investigate the incident, the agency said.
Residents said police set up an exclusion zone at the Reynolds Street site for several hours.
"There was this terrible smell," said Danielle Hodges, a resident living about 400 metres from the well who has complained publicly about headaches and other health problems since moving into a new house six months ago. "There were no workers around at the time."
Ms Hodges said her family, including four children, have also felt regular tremors which they blame on the CSG mining and have reported them to the EPA.
"It can happen around 7am, when there are no trucks around," Ms Hodges said. "What else can it be?"
