Three environmental groups are suing the federal Bureau of Land Management, arguing the agency reopened thousands of acres in southern Utah to unfettered motorized use without investigating the potential environmental impacts.

The groups — the Natural Resources Defense Council, Southern Utah Wilderness Alliance and The Wilderness Society — say off-roading in the area will cause soil erosion, worsen air and water quality and could hurt an endangered species of cactus, according to the lawsuit, filed Thursday in Utah’s U.S. District Court.

The BLM reopened 5,300 acres around Factory Butte in Wayne County, east of Capitol Reef National Park, on May 20, just before Memorial Day. The land around the signature rock formation had been closed to cross-country off-road traffic since 2006, after a petition from SUWA to protect the cactus and soil.

The move also opened the 100-acre Caineville Cove OHV play area, near Caineville of State Road 24.

Previously, the BLM had restricted motorized vehicles to specific routes within the area.

(Photo courtesy of Ray Bloxham | Southern Utah Wilderness Alliance) This photo shot in 2017 shows tracks left by illegal off-roading near Factory Butte, pictured in the distance. The BLM announced in May was reopening the lands encircling the famous southern Utah butte to cross-country motorized travel. The action prompted a lawsuit from three environmental groups to try to reverse the decision.

While the groups filing suit said in a news release they didn’t agree with the BLM’s decision to reopen the land without any sort of notice or public comment period (or to reopen to the land in general), they also believe the agency broke the law.

A BLM representative declined The Salt Lake Tribune’s request for comment, saying the bureau doesn’t comment on pending litigation.

In a news release about the reopening, the BLM said it had been monitoring and installing infrastructure for a decade to protect the endangered cactus species, known as Wright fishhook cactus, so it can “enhance recreational access at Factory Butte,” adding the agency had met “all of the necessary criteria” to reopen to off-roaders.

According to the National Environmental Policy Act, a government agency undertaking a major federal action that affects the environment must assess the likely impacts of whatever project it undertakes.

The groups allege the BLM didn’t do such testing before reopening thousands of acres near Factory Butte to off-roading.

BLM field manager Joelle McCarthy wrote in a May 24 memo regarding the reopening that staffers had installed warning signs, fences and information kiosks in the area to make sure the endangered cactuses in the area were safe from off-roaders.

McCarthy also said the BLM added monitoring measures to keep track of the impacts of off-roading on the cactus population. McCarthy didn’t elaborate on what those monitoring measures were.

Laura Peterson, an attorney with SUWA, said the cactuses are not the only natural resources in the area that should be protected.

“The bottom line is there’s a lot more problems than just the endangered cactus. There is the soil erosion, especially as climate change is becoming more prevalent...,” Peterson said. “It impacts air quality, water quality — all things they should have looked at before opening all this.”

The environmental groups’ lawsuit asks a judge to reverse the BLM’s decision until the agency complies with the National Environmental Policy Act and conducts environmental testing.

Clarification: 10:31 p.m., Aug. 2, 2019 • This story has been changed to clarify what the National Environmental Policy Act requires of government agencies.