A natural gas compressor station proposed for Weymouth has overcome a major obstacle in its approval process. A challenge to the project’s state-issued air quality permit was rejected Thursday, allowing the project to continue its way through the approval process.

The DEP issued an air quality permit for the project in January, allowing the project to move forward. Opponents of the compressor station filed an appeal, which was the subject of hearings in May. Those hearings were extended after the DEP released 759 pages of previously unreleased air quality data two full days into the process.

The hearing officer's decision Thursday to recommend the approval of the air quality permit is a blow to advocates like Alice Arena, who have argued that the natural gas compressor station would burden an already contaminated area with carcinogenic pollutants.

"It feels like a stab in the back from the commonwealth of Massachusetts," Arena said. "There's no other way to put it. The agencies that were installed to protect the health and safety of the citizens have failed."

Arena says it's not over. “We’ve had setbacks before. We've had days when you've said, 'Augh!' You know, you throw your hands up. But it’s not at all over.”

The station still requires several more approvals, including wetlands and Chapter 91 Waterways permits from the state DEP. Both of those permits were issued by the department and are currently under appeal. The project is also being reviewed by the state Office of Coastal Zone Management.

Arena says her group plans to challenge any permit approvals in court.

The compressor station was also recently the subject of a hearing by the federal Pipelines and Hazardous Materials Safety Administration.

“The Commonwealth previously completed a science-based evaluation of air quality and health impacts associated with the proposed project, considered all applicable state and federal requirements and extended the permitting process by nine months to allow for further analysis," DEP spokesperson Katie Gronendyke said in a statement. "Consistent with Department regulations, Commissioner Suuberg will review the Recommended Decision and case record and will issue a Final Decision in the coming weeks.”

The final decision is expected by July 12.