Updated 4:50 PM EST with more details from the memo.

On his first full day as secretary of defense, Mark Esper has signed a memo establishing a task force to deal with cancer-causing chemicals found on military bases.

The purpose, he told reporters at the Pentagon Wednesday, is to “address all the key areas” of the military’s response to the presence of harmful chemicals used in firefighting foam.

The chemicals, perfluorooctanoic acid and/or perfluorooctane sulfonate have been found to have caused contamination at more than 230 military installations, according to an environmental advocacy group. The Environmental Working Group says that harmful levels have been detected in groundwater or drinking water sources of the fluorinated compounds, known collectively as PFAS.

An additional 44 civilian airports are included that are also used by Air National Guard units, according to the group.