A federal court has denied a motion filed by three Pennsylvania senators to intervene in a lawsuit challenging the Delaware River Basin Commission’s (DRBC) ban on horizontal hydraulic fracturing in the 13,539-square mile watershed.

The U.S. District Court for the Middle District of Pennsylvania denied the motion in an order issued Thursday that found the senators have no standing in the outcome of the case. Republican Sens. Joseph Scarnati, who serves as the Senate president, Lisa Baker and Gene Yaw filed to intervene in October. Each represents parts of the state where shale development has been heavy.

In their motion, the senators argued that the DRBC’s ban violates both state law and the authority of the General Assembly to legislate and regulate the oil and natural gas industry.

“DRBC is nullifying the General Assembly’s law-making power by effectively countermanding the directives of duly enacted laws that permit the development of gas well pads, gas wells and related facilities, and that also allow drilling for natural gas in shale formations,” the motion said.

The Wayne Land and Mineral Group (WLMG) filed a lawsuit against the DRBC last May, arguing that the commission is impeding the development of private land and appeasing environmental groups opposed to oil and gas produced by unconventional drilling. WLMG charges that the DRBC lacks authority under the Delaware River Basin Compact to review and approve natural gas development.

The U.S. Congress approved the compact in 1961. It’s an agreement among the United States, New York, Pennsylvania, New Jersey and Delaware to protect the Delaware River watershed. Pennsylvania is a member of seven other interstate river basin organizations.

The senators had also noted that the state did not relinquish its legislative and regulatory powers when it entered the compact. And they argued for a role in the case to protect those powers. The Delaware Riverkeeper Network, an environmental organization that has long been opposed to shale development in the state, filed to intervene in the case in July. The court granted the organization intervenor status in September. The Riverkeeper Network supports the DRBC’s contention that it has authority to impose and advance the moratorium.

The DRBC decided in 2009 that all gas drilling in the basin needed to be reviewed, saying it would not approve any development until it adopted new rules governing the industry. The next year it decided to postpone the review of natural gas development and has failed to act on adopting new rules, leaving in place a de facto moratorium.

WLMG owns about 180 acres of land in Wayne County, PA, which Baker represents. Seventy-five of those acres are within the river basin. According to its lawsuit, the company acquired the property in 2015 with the intent to explore for, extract and sell natural gas from shale formations underneath the property.

The court is permitting the senators to file a friend-of-the-court brief on behalf of WLMG, which must be submitted within 14 days of the Jan. 5 order denying their motion.