Pipeline operator Equitrans Midstream Corp. said Sept. 14 it will consider all remedies against its former parent company EQT Corp. over an ownership dispute for Hammerhead pipeline that runs from Pennsylvania to West Virginia.

Equitrans said it was recently made aware that EQT believed the pipeline was not in service, and that gave the producer the right to terminate gathering agreements with Equitrans and take ownership of the line in exchange for a reimbursement.

EQT, the largest U.S. natural gas producer, was even marketing the pipeline for a sale with its financial advisors under that belief, an action Equitrans said it believes "constitutes unlawful conduct."

Equitrans said that the 1.6 Bcf/d Hammerhead pipeline was, however, placed in-service on Aug. 1, after being completed and injected with initial line-pack—gas stored in a pipeline—provided by EQT in July.

"We firmly believe, and have communicated to EQT, that EQT lacks any valid basis for its actions and that any attempt by EQT to terminate the Hammerhead gathering agreement and to acquire [or potentially sell] the Hammerhead pipeline is contrary to law," Equitrans said in a statement.

EQT in 2018 split into two, separating its midstream operations from the gas production business. It did not immediately respond to a request for comment.

EQT is still the biggest shareholder of Equitrans, holding around 11.7% of the midstream operator, according to the most recently available data from Refinitiv in March.

Equitrans said it remains committed to a resolution, adding that the two companies have usually resolved disputes amicably in the past.