Open-air pits in which toxic materials are burned are still being used at bases in Afghanistan, new data suggests.

A report from the Special Inspector General for Afghanistan Reconstruction warns that at one 13,500-person Marine base in Helmand province in Afghanistan U.S. military and civilian personnel are being exposed to smoke emissions from open-air burn pits that create serious health concerns.

“Toxic smoke from burning solid waste each day increase the long-term health risks for camp personnel,” inspector general John Sopko wrote to commanders of U.S. Central Command and U.S. Forces-Afghanistan. The emissions create elevated risks for, “reduced lung function and exacerbated chronic illnesses, ranging from asthma to chronic obstructive pulmonary disease,” he said.

Military guidelines explicitly say that burn pits can only be used to dispose of refuse in emergency situations until approved incinerators can be obtained. Camp Leatherneck already spent $11.5 million to purchase and install two 12-ton and two 24-ton capacity incinerators, yet his inspectors found that the 12-ton incinerators were being underutilized and the larger incinerators were not being used at all. Moreover, the five-year-old camp was moving forward with a $1.1 million contract to haul solid waste to a local landfill that Sopko says is not necessary. The marines, sailors and government contractors on the base generate about 54 tons of solid waste each day. All that waste could be processed if the incinerators were operated 18 hours a day according to Sopko’s department.

The news comes after a similar inspection led to the revelation in April that another base in Afghanistan, Forward Operating Base Salerno, was continuing to use open-air burn pits despite spending $5 million for incinerators.

The burn pits have been in congressional crosshairs for several years. Last month, Reps. Tim Bishop (D-NY) and Diana DeGette (D-Colo.), introduced new legislation that would establish three Centers of Excellence focused on the prevention, diagnosis, mitigation, treatment, and rehabilitation of health conditions related to burn pits and associated environmental exposures.