An agreement approved Monday between U.S. officials and environmentalists would ban the use of predator-killing cyanide traps on Colorado public lands, but a government agency said federal workers already had stopped using the devices except on the state’s private lands. Public pressure for a nationwide ban on the traps — meant to protect livestock from predators — has increased since an Idaho teen was injured and his dog killed by one in March. The environmental groups WildEarth Guardians and the Center for Biological Diversity sued the government earlier this year alleging cyanide traps kill wildlife and pets indiscriminately. Under Monday’s agreement, which was approved by U.S.