During the Cold War, U.S. nuclear munitions included 1,000 Minuteman missiles. Construction on the Minuteman II structures began in 1946. Whiteman Air Force Base (AFB) was headquarters for the 510th Strategic Missile Squadron of the 351st Strategic Missile Wing, consisting of 150 Minuteman II Intercontinental Ballistic Missile (ICBM) silos and 15 launch control facilities spread over 14 counties of west central Missouri. Whiteman AFB was also home to the Oscar-01 Missile Alert Facility (MAF). The Oscar-01 was the only MAF built inside an air force base. All other Minuteman II missile silos and launch control facilities were built in rural areas that surrounded the base.
Between 1996 and 1998 the missile silos were deactivated/ dismantled under the Strategic Arms Reduction Treaty I (START I) and are now going through the minimum five-year environmental monitoring process.
Missouri Department of Natural Resources’ Role
Department staff are involved in reviewing, commenting on and supporting various activities conducted during cleanup of federal sites. The department works with the U.S. Air Force (USAF) and the U.S. Environmental Protection Agency (EPA) to ensure the continuing safety of these closed missile sites through inspections and owner education.
The USAF's 165 Minuteman II missile sites were decommissioned in the 1990’s as the result of START I. During the closure process, the USAF discovered that waterproofing materials used in the construction of the missile silos and on underground storage tanks (USTs) contained polychlorinated biphenyls (PCBs).
Contaminants of Concern
The contaminants of concern for these sites are diesel fuel, PCBs and asbestos.
What’s Been Done
Closure of the former Minuteman II missile sites included demolishing and capping silo structures and closing the USTs, which included removing soil contaminated with diesel fuel. Some diesel fuel may remain on-site at concentrations that are not a risk to human health. The remaining diesel fuel concentrations are decreasing through a process called natural attenuation, in which microorganisms in the soil break down the chemicals into nontoxic substances.
A groundwater investigation spanning five years confirmed that the PCBs remained trapped within asphaltic material that was buried during closure. The PCBs are not migrating into groundwater. Preventing human contact with PCBs is important because PCBs are toxic compounds that stay in the environment and do not break down over time.
What’s Left
Department staff conduct follow-up visits at properties where the USAF’s annual inspections indicate a change of land use or property ownership. Department staff assist the USAF with developing and implementing a system to update property ownership records, which helps in continued outreach with site owners.
Details
A launch facility implodes as the U.S. complies with the START I Treaty. The Minuteman II blows into history.
What are the Minuteman II sites?
Whiteman AFB housed the USAF 351st Strategic Missile Wing, which managed the Minuteman II ICBM deployment area in west central Missouri. The wing operated 150 Minuteman II missiles in underground launch facilities, or silos, and 15 launch control facilities that were scattered across a 16,000 square mile area encompassing sections of 14 counties.
Missile deployment began on Sept. 1, 1963. As a result of START I, President George H. W. Bush issued an order on Sept. 28, 1991, to take Minuteman II missiles off alert status. In July 1992, site deactivation began with removing the missiles and associated equipment, such as standby diesel generators, critical and classified items and salvageable and reusable components. The USAF dismantled the 150 Minuteman II Missiles, imploded the underground silos and deactivated 14 of the 15 launch control facilities from service at 164 of the off-base properties. The last silo was imploded in December 1997.
Oscar-01 is the only remaining launch control facility. Located at Whiteman AFB, the USAF maintains Oscar-01 as a Minuteman II museum. The Oscar-01 is available to the public for scheduled tours.
The Problem
During the closure process, the USAF discovered that waterproofing materials used in the construction of the missile silos and on underground storage tanks (USTs) contained polychlorinated biphenyls (PCBs). Non-liquid PCBs above 50 parts per million were found on the outer surface of the silos and in and around the USTs and associated piping. Several USTs were found to be leaking diesel fuel. In addition, asbestos was discovered in the protective coating on the USTs and underground piping.
Environmental Restoration
As required by the 1995 Federal Facilities Compliance Agreement (FFCA) and 1995 Participating State Attachment to the FFCA, the USAF buried and capped all PCB-containing debris inside the silos. Above ground and underground portions of the launch control facility structures were left in place and not imploded. Pipes from the USTs to each support building were removed. The USTs were removed or cleaned, filled with sand and left in place. Soil contaminated with diesel fuel, mostly the result of fuel spills, was removed.
Institutional controls in the form of use restrictions, covenants and deed notices were defined in the documents transferring title of the property from the U.S. government to private landowners. The institutional controls are required to be included in any subsequent transfer of the sites. These use restrictions, covenants and deed notices are necessary to protect human health and the environment due to the persistent nature of PCBs.
What’s Left
Today, most of the former Minuteman II sites are used for secure storage of hay, equipment and vehicles. Many of the sites continue to be used to support farming operations since being transferred into private ownership. Some sites remain vacant.
Looking to the Future
The former Minuteman II sites will continue to undergo long-term monitoring, as described in the Long-Term Stewardship Agreement for the Missouri Minuteman II Missile Sites, June 2007. Adherence to land use restrictions through property owner education is a critically important part of the department's continued stewardship of the former missile sites. Property owners must request a waiver of the restrictions if planning any alterations or improvements that will disturb the ground surface. Waivers may be requested from either EPA or the department by filling out a Former Minuteman Missile Site Property Change Request MO 780-2040.
