Carbondale trustees decided Tuesday that the town should join a new lawsuit as a co-plaintiff in the continuing court battles over the Thompson Divide.

This is the second litigation that Carbondale has recently entered concerning the Bureau of Land Management’s record of decision in November to cancel 25 oil and gas leases in the Thompson Divide.

The Texas-based energy company SG Interests held 18 of those leases, and in February the company filed a lawsuit challenging their cancellation. In response, Pitkin County and the Carbondale-based conservation group Wilderness Workshop became intervening parties in the lawsuit, defending the BLM’s decision to cancel the oil and gas leases. In April, Carbondale joined in as another party supporting the BLM’s decision, along with Thompson Creek Cattlemen’s Association and Trout Unlimited.

Since then, Pitkin County and Wilderness Workshop have filed a stand alone lawsuit they’ve described as an “insurance policy,” in case the judge overturns the BLM’s decision in SG’s case.

This new lawsuit deals with a different aspect of the Thompson Divide leases — namely, that the BLM wrongfully extended the Thompson Divide leases in 2014, 2015 and 2016. Rather, the BLM should have let them expire in 2013, the lawsuit contends.

In the second litigation, trustees have become full-blown co-plaintiffs.

In that lawsuit, the complaint “asserts that the leases should have been allowed to terminate for lack of development during the ten-year primary terms, rather than suspended,” according to a memo from Mike Chiropolos, Carbondale’s attorney in the Thompson Divide lawsuits.

“This legal strategy would complement intervention in the case filed by SG challenging BLM’s decision to cancel the 18 unlawfully issued SG leases in Thompson Divide,” he wrote.

On Tuesday, he described the second lawsuit as a backup plan to allow these parties to continue to be on record challenging the BLM’s decision to suspend the leases.

If SG’s initial lawsuit is dismissed or settled, then the second lawsuit becomes a moot point.

Trustees received legal advice from Chiropolos in an executive session during their April 25 meeting. And on Tuesday that had few questions for the attorney beyond how many billable hours he anticipated spending, which is estimated at 20 on the high end. The board unanimously approved joining the lawsuit.