In 1983, investigations had shown soil and water contamination with degreasers and JP-4 jet fuel, and in 1990 the base was put on the National Priorities List of superfund sites.

Pease Air National Guard Base is approximately 220 acres (89 ha) in size, and as of September 2014 included 46 structures.

[4] It is located approximately 50 miles (80 km) from Manchester, Portland, and Boston[5] — major cities of New Hampshire, Maine, and Massachusetts, respectively.

[7] The airport was closed to civilian traffic effective August 1942, as part of defense measures along the east coast.

[8] Civil Air Patrol usage started in February 1944,[9] and in August the airport was leased to the U.S. Navy,[10] who already had a nearby presence at Portsmouth Naval Shipyard.

Redesignated as the 509th Bombardment Wing, Medium, the 509th had no bomber aircraft from November 1969 until 1970, but continued KC-135 refueling and alert operations and performed FB-111 ground training.

[citation needed] In December 1988, Pease AFB was one of 86 military installations to be closed as part of the Secretary of Defense's Base Realignment and Closure process.

In 1989, 3,461 active-duty military, 741 civil service workers and 347 non-appropriated fund employees were employed at Pease AFB.

The KC-46A was scheduled to enter the Air Force inventory during fiscal year 2016, with Pease ANGB to receive its first Pegasus after October 2017.

[28] The final KC-135 at Pease, serial number 57-1419, departed on March 24, 2019, for Goldwater Air National Guard Base in Phoenix, Arizona.

On November 20, 1957, a KC-97 from Dow Air Force Base in Maine made an emergency landing at Pease after its refueling boom could not be retracted; there were no injuries.

[33][34] On April 15, 1958, a B-47 (serial number 52–0562) from Walker Air Force Base in New Mexico crashed on takeoff at Pease; all four crewmen were killed.

[35][36][37] On July 22, 1959, a KC-97 (serial number 52-2703) crashed near Andover, New Hampshire, while on a nighttime training mission; all seven crewmen were killed.

[46][47][37] On February 26, 1965, a B-47 (serial number 52-0171) returning to Pease from Spain was involved in a mid-air collision while refueling over the Atlantic Ocean with a KC-135 from Dow Air Force Base; the four crewmen on each plane were killed.

[52][53] Both crewmen successfully ejected, and there were no fatalities on the ground; however, the resulting fires in a housing complex caused $385,000 ($1.29 million in 2023) in damages and left 13 families homeless.

[72] Aircraft maintenance operations at Pease AFB generated hazardous waste, including spent degreasers, solvents, paint strippers, jet fuels, and others, which contaminated soils and groundwater.

[73] The site's contamination is addressed in twelve long-term remedial phases,[74] mainly soil excavation and disposal, vertical containment walls installed in the subsurface and groundwater extraction wells, soil vapor extraction and air sparging to treat petroleum and solvent contamination, and where groundwater extraction and treatment efforts are uncertain (zone 3) improvement thereof and wellhead preparing treatment capability for the Haven water supply well.

[76] In 2015, the CDC announced blood testing of 500 people exposed to this contaminant from the Haven Well, thought to stem from the Air Force using firefighting foam.

[75] In mid July, the New Hampshire State Department of Health and Human Services announced it was "exploring all measures to reopen testing for anyone exposed to contaminated water" at Haven Well.

An international/domestic passenger terminal has Federal Inspection Services including U.S. Customs and Border Protection, agriculture and immigration.

[84] In 1992, a former weapons storage area in Newington, approximately 1,100 acres (450 ha) with frontage on Great Bay, was turned into a wildlife refuge.

[88] Staffed primarily with retired veterans and local residents,[88] the group was joined by former President George H. W. Bush in greeting a flight in October 2010.