More than 120 countries have joined a convention banning their use as inhumane and indiscriminate, in large part because of high failure rates that litter the landscape with unexploded submunitions that endanger both friendly troops and civilians, often for decades after the end of a conflict. The United States, Ukraine and Russia — which is alleged to have used them extensively in Ukraine — are not parties to the convention. Eight of NATO’s 31 members, including the United States, have not ratified the convention.
The principal weapon under consideration, an M864 artillery shell first produced in 1987, is fired from the 155mm howitzers the United States and other Western countries have provided Ukraine. In its last publicly available estimate, more than 20 years ago, the Pentagon assessed that artillery shell to have a “dud” rate of 6 percent, meaning that at least four of each of the 72 submunitions each shell carries would remain unexploded across an area of approximately 22,500 square meters — roughly the size of 4½ football fields.
“We are aware of reports from several decades ago that indicate certain 155mm DPICMs have higher dud rates,” said a defense official, one of seven Pentagon, White House and military officials who spoke on the condition of anonymity to discuss the sensitive decision. The defense official used the acronym for Dual Purpose Improved Conventional Munitions.
The Pentagon now says it has new assessments, based on testing as recent as 2020, with failure rates no higher than 2.35 percent. While that exceeds the limit of 1 percent mandated by Congress every year since 2017, officials are “carefully selecting” munitions with the 2.35 percent dud rate or below for transfer to Ukraine, Pentagon spokesperson Brig. Gen. Patrick Ryder said Thursday.
There is no waiver provision in the 1 percent limit Congress has placed on cluster munition dud rates, written into Defense Department appropriations for the last seven years. Biden would bypass it and Congress, according to a White House official, drawing down the munitions from existing defense stocks under a rarely used provision of the Foreign Assistance Act, which allows the president to provide aid, regardless of appropriations or arms export restrictions, as long as he determines that it is in the vital U.S. national security interest.
The final U.S. decision to provide them to Ukraine was first reported Thursday by the Associated Press.
A 2022 Congressional Research Service report to lawmakers noted “significant discrepancies among failure rate estimates” of cluster weapons in the U.S. arsenal, with some manufacturers claiming 2 to 5 percent, while mine clearance specialists have reported rates of 10 to 30 percent.
Nonproliferation experts said that the Pentagon’s assessed 2.35 percent dud rate most likely refers to aging shells with updated fuses designed to improve their ability to self-destruct, but that it was impossible to know without access to the testing data.
“It’s dismaying to see the long-established 1 percent unexploded ordnance standard for cluster munitions rolled back as this will result in more duds, which means an even greater threat to civilians, including de-miners,” said Mary Wareham, advocacy director of the arms division of Human Rights Watch.