The U.S. Army plans to manufacture and use eco-friendly bullets that will still kill people but won’t be quite so deadly to the environment. New tungsten-based bullets will be phased in as replacements for traditional lead bullets, which can cause lead buildup in the environment and contaminate sediments, surface water, and groundwater. Some 1 million “green” bullets will be produced this year, primarily for use in target practice, with that number rising to 200 million in coming years.