Environmental regulators in New South Wales, Australia, have ordered oil and gas producer Santos to improve operations at its Narrabri coal seam gas (CSG) project after wastewater leaks.

Following an investigation into two separate incidents which occurred in 2013 and 2015, the New South Wales Environment Protection Authority (EPA) concluded that neither incident resulted in any significant environment impacts. However, the agency expressed concern over aspects of the site operations and management.

Santos now has to comply with two Pollution Reduction Programs (PRPs). These require the company to improve its groundwater monitoring and verify the operation of vents and flow lines used within the Narrabri gas field, explained EPA Chief Environmental Regulator Mark Gifford.

"We will be monitoring the implementation of the PRPs to ensure the company is meeting its obligations," Gifford added.

The EPA also said it was important that the company was more open and timely in declaring any incident, "regardless of the size or impact".

"CSG is a highly emotive issue within local communities around the area. Prompt communication about an incident will assist the community's understanding of the activities and foster stronger relationships," Gifford said.

In the first incident, in May 2013, Santos detected "slightly elevated levels of salinity and heavy metals" in groundwater close to ponds that are used to hold produced water from coal seam gas operations.

According to the EPA there is insufficient evidence to determine whether the changes detected in groundwater were the result of leaks from the ponds. But a PRP will be placed on the company's environment protection license, requiring it to increase its monitoring program and prepare a groundwater monitoring report to examine the source of the elevated concentrations and to evaluate changes to groundwater flow conditions at the site.

In the second incident, in January 2015, produced water was emitted from a vent on Santos' Dewhurst Southern Water Flow Line.

The EPA ruled that the company did not breach its environment protection license. But it will attach a PRP to the license, setting out strict operation and maintenance requirements for the vents and flow lines used within the Narrabri gas field to prevent a similar incident from occurring in the future.