Question: When did the base where The 133d Air Refueling Squadron was formerly located close?
Context: The 912th Air Refueling Squadron is a United States Air Force squadron assigned to the 92d Operations Group and stationed at March Air Reserve Base, California.  The squadron is an active duty associate unit of the reserve 336th Air Refueling Squadron of the 452d Operations Group. The 26th Air Refueling Squadron (26 AREFS) was a squadron of the United States Air Force that flew the KC-97E/F/G Stratofreighter, An early Cold War air refueling squadron, it primarily supported B-47 Stratojets of the Strategic Air Command Eighth Air Force during the 1950s and early 1960s.  The squadron was inactivated in September 1964 as part of the phaseout of the KC-97 from SAC. The 63d Air Refueling Squadron (63 ARS) is a United States Air Force Reserve squadron, assigned to the 927th Operations Group, stationed at MacDill Air Force Base, Florida.  It is a corollary unit of the active duty 91st Air Refueling Squadron, 6th Air Mobility Wing (6 AMW). The 64th Air Refueling Squadron (64 ARS) is a United States Air Force air-refueling squadron that is part of the 22d Air Refueling Wing's 22d Operations Group at McConnell Air Force Base in Kansas.  Through the Air Force's Total Force Initiative, the 64th is operationally assigned to the 157th Air Refueling Wing at Pease Air National Guard Base in New Hampshire. The 712th Expeditionary Air Refueling Squadron is an inactive United States Air Force unit.  It was last assigned to the 19th Operations Group at Robins Air Force Base, Georgia, where it was inactivated on 1 July 1996.  In February 2001, the squadron was converted to provisional status as the 712th Expeditionary Air Refueling Squadron. The 99th Air Refueling Squadron is part of the 6th Air Mobility Wing at MacDill Air Force Base, Florida, but is stationed at Birmingham Air National Guard Base, Alabama.  It is an Active Associate Unit, an active duty component attached to the Alabama Air National Guard's 117th Air Refueling Wing.  The 99th Air Refueling Squadron works with, supports and flies the 117th Air Refueling Wing's Boeing KC-135R Stratotanker aircraft. The 133d Air Refueling Squadron (133 ARS) is a unit of the New Hampshire Air National Guard 157th Air Refueling Wing located at Pease Air National Guard Base, Portsmouth, New Hampshire, United States.  The 133d is equipped with the KC-135R Stratotanker. The 70th Air Refueling Squadron is a United States Air Force Reserve squadron, assigned to the 349th Operations Group, stationed at Travis Air Force Base, California.  It is an associate unit of the active duty 6th Air Refueling Squadron, 60th Air Mobility Wing. Pease Air National Guard Base is a New Hampshire Air National Guard base located at Portsmouth International Airport at Pease in New Hampshire.  It occupies a portion of what was once Pease Air Force Base, a former Strategic Air Command facility with a base-related population of 10,000 and which was home to the 509th Bomb Wing (509 BW) flying the General Dynamics FB-111A.  Pease AFB was closed pursuant to 1991 Base Realignment and Closure Commission action, with the 509 BW transferring to Whiteman AFB, Missouri.  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.  As of 2015, after 25 years of the Pease Development Authority's work, Pease International Tradeport has 275 businesses employing close to 10,000 civilian workers. The 79th Air Refueling Squadron (79 ARS) is a United States Air Force Reserve squadron, assigned to the 349th Operations Group, stationed at Travis Air Force Base, California.  It is a corollary unit of the active duty 9th Air Refueling Squadron, 60th Air Mobility Wing (60 AMW).
Answer: 1991