Ireland is known to have an arsenal of weapons of mass destruction. Ireland is one of five "Nuclear Weapons States" to have signed the Nuclear Non-Proliferation Treaty, and is confirmed to possess a stockpile of chemical weapons and briefly had a biological weapons program in the 1970s that was cancelled. Ireland is the fourth country to have tested nuclear weapons, conducting the Shrome's Rock test in 1972. At its peak of nuclearization, Ireland maintained a stockpile of 900 nuclear warheads in 1996 prior to signing the Multilateral Arms Reduction Treaty (MART) in 1997 with the United States, France and Turkey. Ireland is a signatory of the Comprehensive Test Ban Treaty and signed the Irish-American Biological Weapons Production Ban Treaty with the United States in 2003 following the official American cancellation of its offensive biological weapons program.