By Johanna Evans
There were no warnings on the fence, but as we stood here filming a noisy coal seam gas (CSG) well in the Pilliga Forest in early March 2024 we became unwell very quickly. We were there as part of the GasWatch initiative, a community monitoring program introduced by NWPA in 2019 in response to perceived lack of governmental/regulatory oversight of the Santos Narrabri Gas Project.
Our eyes were burning, we felt nauseous, I developed a headache, my colleague felt dizzy and we could smell a metallic odour not dissimilar to rotten egg gas – Hydrogen Sulphide (H2S), a colourless, flammable gas which is the tell-tale sign of a “sour” gas field, and often associated with higher levels of CO2.
The symptoms took just five minutes to emerge and continued for an hour afterwards. It was obvious it was the green tank in the corner of the Dewhurst 28 site, known as a “break tank”, that had caused our symptoms. We knew immediately that we must leave the area.
What is a break tank?
In CSG extraction break tanks (or degassing tanks) are used when there is insufficient pressure to “push” the water into the gathering system. Instead, the water flows to a tank where it is pumped back into the gathering line. In this case the tank is open to the atmosphere. This allows vapour and gases to escape during rapid filling (vapour is pushed out) or emptying (vapour is sucked in). These emissions include methane (CH4) and other poisonous, toxic gases. The tank is not a closed system and consequently gases and contaminants are freely liberated from the tank.
Our experience at the site of this break tank, located at the Dewhurst 28 CSG well in the Pilliga State Forest, spurred us to investigate further and subsequently a pollution complaint was sent to the NSW EPA.
GIPA 1032 Timeline & Documents
We were concerned that others, including Santos’ workers and contractors, might have the same serious reaction or worse. H2S has a distinctive odour of rotten eggs at low concentrations of 0.01 to 0.03ppm, which is an excellent warning sign. However, at higher and more dangerous concentrations of around 100ppm, neurotoxicity occurs.
This particular break tank had been operating for 10 years before it was removed and had the capacity to hold 38,000L of produced water. It operated continuously whilst the well was producing. You do see a few break tanks in gasfields although they are not common, they are rarely discussed in company literature and their regulation is complicated.
The first complaint
This complaint (Doc 027a) was not seriously investigated by the EPA at the time and it was only when a subsequent complaint was made by a high-profile NGO that the EPA attended with monitoring equipment to conduct an investigation. By this time, environmentalists were becoming increasingly concerned about the Dewhurst 28 break tank, prompting one group to apply for documents under Government Information Public Access (GIPA). Documents reveal this GIPA took 10 months to complete, during which time the break tank was removed from the site although nowhere in the documents is this mentioned.
Why were neither of the complainants or the applicant or the Narrabri Gas Project Community Consultative Committee informed that the tank was being investigated and had been removed? NSW resources conducted an audit in December 2024 and inspected Dewhurst 28. Did Santos inform NSW Resources of the concern around the break tank?
The second complaint
We returned to Dewhurst 28 in June 2024 with the Investigations Team from Australian Conservation Foundation and a FLIR Optical Gas Imaging (OGI) camera. The camera revealed continuous emissions from the vents on top of the tank.
ACF subsequently lodged their own complaint with the EPA stating “During an investigation with a FLIR OGI camera on 8th and 10th June 2024, the top of the break tank at a gas installation called Dewhurst 28, was observed to be continually emitting a combination of methane and other VOCs. ACF investigators observed the tank at two different times of day, two days apart, on the 8th and 10th of June. Similar volumes of emissions were detected on both days. We observed continuous emissions from the top of the break tank. Despite wearing N95 masks, the team could smell and taste VOCs in the air and some attendees reported headaches.”
Reporting Black Hole – vanishing emissions
The EPA investigation lasted 46 minutes and failed to detect H2S or VOCs (Doc 092H). The report is 13 pages, 11 of which are photographs and did not mention VOC’s or H2S. The Eagle Gas Monitor used by the EPA detected a maximum concentration of 1600ppm methane (CH4). “Approximately 15cm from the source point fluctuated at between 25ppm and 510ppm.The EPA will be taking follow up action relating to this incident by making further lines of enquiries regarding the matter.”
ACF asked the EPA “Where, under EPL 20350, are break tanks regulated as to their emissions?” The EPA response was “Section 1, Condition A2 and Section 8, Condition E3 under EPL 20350.” When you cross reference this you will see the first condition relates to the premises and the second condition to Environmental Liability Insurance.
Then, EPA relay to ACF exactly what Santos told them (Doc 31a): “The Clean Energy Regulator (CER) for the National Greenhouse and Energy Reporting (NGER) regulates the emissions from the break tanks and are included in the fugitive emissions reported for produced water. The fugitive emissions are calculated from the produced water volumes per well for the reporting period. The salinity referenced to determine the applicable emissions factor is obtained from Leewood Produced Water Facility. The National Pollution Inventory (NPI) does not include greenhouse gas emissions which are reported under NGER, therefore methane is not reported under the NPI. Hydrogen sulphide is a reportable substance under the NPI if the reporting threshold of 10 tonnes per year is exceeded.”
There is a black hole around VOC’s and H2S in Pel 238. Santos reports zero H2S as an Assessable Load to the EPA for fee-based licencing but it is most certainly being produced. We know that removing the tank does not remove the emissions and that they will find their way into the air further downstream via high point vents or other venting infrastructure.
In a report by Dr Marion Lloyd Smith for the National Toxics Network, it states: “The air pollution identified in this report indicates an urgent need for all current natural gas development sites including well pads, compressors, gas plants, and waste sites to undergo continuous monitoring for volatile organic compounds and hydrogen sulfide and to provide that data to regulators and the public.
There is a known link between carbon dioxide (CO2) and H2S. We know from our independent investigation of gas composition data that the Narrabri Gas Project area has raised levels of CO2.
It is intriguing that in Document 091, an EPA internal email (which appears to have some detail obscured) that there is mention of the filing of the sub-par Inspection Report; “to be the EPA’s independent “truth” source moving forward”. Does this mean that there is another inspection report?
It would be pertinent to correctly assess and quantify the highly toxic gases from CSG operations and invest in better technology so they are not being returned to the air. Regulators could consider that pieces of equipment that vent toxic gases need warning signage. Greater transparency is required with the public and possibly the EPA given that Santos seemingly told nobody of their decision to remove the break tank. We call on the NSW EPA to conduct an assessment of all air toxics at all break tank sites in the Pilliga and make the data publicly available.
Note: Upon reading the Inspection Reports included in the GIPA it appears EPA no longer have access to any of the Santos owned CSG wells and are required to stay at the public boundary to conduct their inspections. How can compulsory regulatory LIDAR inspections be conducted competently from 20+ metres away?