For decades, potentially explosive waste has been burned in the open in the western part of the Salt Lake Valley, starting with dynamite and now unspent rocket propellant produced by defense contractor Northrop Grumman and its subsidiary ATK Launch Systems.

Now, several groups are asking the Utah Department of Environmental Quality to put an end to the practice, citing well-established alternatives for processing such reactive wastes with far less emissions.

“Why on earth, in this day and age, are we allowing one of these toxic burn pits to operate in the Salt Lake Valley? It is such an anachronism,” said Brian Moench, president of Utah Physicians for a Healthy Environment. “Combustion of toxic materials is an inappropriate way to deal with it.”

The group was among those to submit comments as part of a review by the Utah Division of Waste Management and Radiation Control of a proposed 10-year renewal of ATK’s waste storage and treatment permit.

Acquired two years ago by Northrop Grumman, ATK produces rockets at the sprawling Bacchus facility in the far western fringes of West Valley City. Reactive wastes are stored and processed on a small piece of land owned by the U.S. military, known as the Naval Industrial Reserve Ordnance Plant, or NIROP, located near 8400 West and 4100 South. The site, which features storage bunkers, 17 burn pans and two burn cages, is about a mile south of Magna subdivisions.

ATK operates NIROP under contract with the Navy. Its state permit allows the military contractor to burn up to 160,000 pounds of explosives, propellant and other reactive waste each year, but on average it burns about 100,000 pounds annually, according to DEQ spokesman Jared Mendenhall.

(Photo courtesy of Utah Department of Environmental Quality) For decades, highly reactive waste has been burned at the Naval Industrial Reserve Ordnance Plant (NIROP) in West Valley City. This photo depicts one of the cages in which rocket propellant and other dangerous wastes are burned each year with no emission controls. Environmental groups are asking Utah regulators to require defense contractor Northrop Grumman to dispose of this material in safer ways. This photo is included in Northop's draft permit, now under review by the Utah Department of Environmental Quality.

“It is so reactive it is not safe to move,” Mendenhall said. “We have on-site and off-site soil sampling looking for dioxins and other materials that indicate incomplete combustion and compare it to background levels.”

Reached Friday, Northrop spokesman Vic Beck said he was not prepared to offer comment.

The Hercules Co. established the 10,000-acre Bacchus facility in 1915 for manufacturing commercial blasting powder, but the site was repurposed in 1958 for the development and production of solid rocket motors.

A national consortium of environmental groups called the Cease Fire Campaign contends open burning results in the uncontrolled release of toxic emissions into the environment. The waste incinerated by ATK produces perchlorates and PFAS, or polyfluoroalkyl substances, compounds that can harm the human endocrine system.

“The state and the U.S. [Environmental Protection Agency] have the opportunity and duty to impel the military and its contractors to utilize treatment technologies that protect workers, service members and communities from exposure to toxic emissions caused by the open burning of munitions wastes,” said Laura Olah, national coordinator for the Cease Fire Campaign. “No other industry is allowed to open-burn its hazardous waste.”

According to her group’s comments, perchlorate concentrations in groundwater at the Bacchus facility have been detected at levels as high as 19,000 micrograms per liter, more than a thousand times the federal health standard for drinking water, and contamination has migrated several miles off-site.

“Moreover, perchlorate released directly to the atmosphere is expected to readily settle through wet or dry deposition,” Olah wrote in the formal comments. She outlined various techniques used elsewhere that have been shown to dispose of similar waste more safely.

One example cited is called gas phase chemical reduction, which uses hydrogen and heat to break down toxic chemicals into their basic components. Because oxygen is not present in this process, no harmful chlorinated byproducts are formed. Olah complained that ATK has not submitted any analysis of such alternative waste-disposal processes as part of its permit renewal.

“If the NIROP permit is granted,” the group wrote, “it should expire in no more than one year to allow for and to motivate the deployment of safer treatment technologies — ending decades of open air burning of hazardous waste that is no longer defensible.”

Under the draft permit, ATK may burn up to 4,500 pounds of explosive waste in a single day, usually during daylight hours only and subject to the weather. Burning at the site is limited during the winter inversion season, when the valley’s airshed is sometimes filled with unhealthy levels of particulate pollution, but ATK may still burn up to 400 pounds on designated “no burn” days.

The burn residues are disposed of at the Grassy Mountain hazardous waste landfill in Tooele County operated by Clean Harbors.