Although the Netherlands does not have weapons of mass destruction made by itself, the country participates in the NATO nuclear weapons sharing arrangements and trains for delivering United States nuclear weapons. U.S. nuclear weapons were first stored in the Netherlands in 1960. The Netherlands is also one of the producers of components that can be used for creating deadly agents, chemical weapons and other kinds of weapons of mass destruction. Several Dutch companies provided the United States, Israel and Pakistan with components for these weapons. The Netherlands ratified the Geneva Protocol on 31 October 1930. It also ratified the Biological Weapons Convention on 10 April 1972 and the Chemical Weapons Convention on 30 June 1995. United States-NATO nuclear weapons sharing The Netherlands ratified the Nuclear Non-Proliferation Treaty (NPT) on 2 May 1975. In the past (1960s till 1990s), the Netherlands took part in the deployment of NATO nuclear artillery shells for its self-propelled howitzers and missile artillery units. These 8 inch shells and warheads for Honest John, and later Lance, missiles were stored at the special ammunition stores at 't Harde and Havelterberg. These weapons are no longer operational. Until 2006, Royal Netherlands Navy P-3 Orion aircraft, and their predecessors the P-2 Neptunes, based at former Naval Air Station Valkenburg in Katwijk and Curaçao in the Caribbean were assigned U.S. Navy Nuclear Depth Bombs (NDB) for use in anti-submarine warfare. These weapons were originally the Mk 101 Lulu, which yielded 11 kt; later, they were replaced by the Mk-57 (also referred to as the B-57). The NDBs were stored under U.S. Marine guard at RAF St. Mawgan, Cornwall, UK, which also held 60 similar weapons for the use of RAF Shackleton and Nimrod aircraft. The storage arrangements were agreed in 1965 between the British Prime Minister Harold Wilson and President Johnson in a secret memorandum now declassified in the UK archives. At present (2008), the USAF still provides 22 tactical B61 nuclear bombs for use by the Netherlands under the NATO nuclear weapons sharing agreement. These weapons are stored at Volkel Air Base and, in time of war, they may be delivered by Royal Netherlands Air Force F-16 warplanes. (The Dutch government has never formally admitted or denied the presence of these weapons, but former prime ministers Dries van Agt and Ruud Lubbers both acknowledged their presence in 2013.) The U.S. insists that its forces control the weapons and that