The justices on Monday left in place a federal appeals court ruling that more than 60 lawsuits over the burn pits could not go forward.
The lawsuits said military contractor KBR dumped tires, batteries, medical waste and other materials into open burn pits. The suits claimed the resulting smoke caused neurological problems, cancers and other health issues in more than 800 service members. The complaints said at least 12 service members died.
The appeals court said KBR was essentially under military control and had little discretion in deciding how to manage the waste. KBR's attorney said the decision to use burn pits "was made by the military."
KBR was formerly owned by Halliburton Corp.