ALBUQUERQUE – Democratic members of New Mexico’s congressional delegation are renewing their pleas for federal land managers to limit oil and natural gas drilling in the northwestern corner of the state over concerns about archaeological and cultural sites that dot the region.

U.S. Sens. Tom Udall and Martin Heinrich and Reps. Ben Ray Lujan and Michelle Lujan Grisham sent a letter this week to the acting state director of the Bureau of Land Management in New Mexico.

There have been concerns that the Trump administration could relax rules that have provided a buffer around Chaco Culture National Historical Park.

While the agency has deferred the leasing of several parcels within the buffer zone, critics say there are more parcels that should be excluded while officials work to update the resource management plan for the region.

“Gas development is critically important to New Mexico’s economy, and it is important that leasing and development is done in a responsible manner that minimizes negative impacts, especially on rural, low-income and tribal communities,” the letter reads.

The delegates say they’re particularly concerned about some parcels that are proposed for an oil and gas lease sale scheduled in March. They pointed to a fire at a production site in July 2016 that prompted the evacuation of several dozen residents from the Navajo community of Nageezi.

Environmentalists say they want to see the March sale canceled all together.

In the letter, the lawmakers ask for the Bureau of Land Management to use discretion and to review the current stipulations that govern oil and gas operations near homes and other structures to ensure safe distances as they work on revamping the overall management plan.

Agency spokeswoman Allison Sandoval said Thursday officials are reviewing the delegates’ letter and noted that the planning process is ongoing.

A world heritage site, Chaco park and its outlying archaeological remnants are at the center of the fight over expanded drilling in the San Juan Basin. Environmentalists have long complained about pollution from fossil fuel extraction and coal-fired power plants in the region, and now tribal leaders and archaeologists have joined in with concerns about the potential effects on cultural resources that span what they refer to as “the greater Chaco area.”

The critics have asked for a moratorium on drilling, saying increased development has the potential to destroy parts of the landscape that could provide a better understanding of the ancient civilization that once inhabited the area.

Oil and gas developers have said they can operate in a way that protects significant sites. They point to existing regulations that require reviews to ensure important areas are not disturbed.

The most recent quarterly lease sale resulted in more than $30 million in competitive bids for parcels in southeastern New Mexico and a record was set for the highest bid per acre. The combined bids are shared by the federal government and the state, which uses revenues and royalties from the industry to fund education and other government services.