Calling all engineers: The Department of Defense is on the lookout for a new bullet that will sprout seeds, instead of waste, after it’s shot.

In a call for proposals, the DoD says that the U.S. Army uses “hundreds of thousands of training rounds” across the country and world. These rounds are left on the ground or just beneath the surface, which is an issue for a few reasons. For one, the components take hundreds of years to biodegrade. When corroded, they could pollute nearby soil and water. Additionally, civilians such as farmers and construction crews who encounter the remnants don’t know if they’re training or tactical rounds.

To solve these problems, the DoD is looking for a bullet casing that eliminates environmental hazards. Embedded in the biodegradable composites will be bioengineered seeds from the U.S. Army Corps of Engineers’ Cold Regions Research and Engineering Laboratory that don’t begin to germinate until they’ve been in the ground for several months. The DoD wants these seeds to produce eco-friendly plants that remove soil contaminants and consume the biodegradable debris from the bullets. It’s important that animals can eat the plants without getting sick.

The rounds needed include:

  • low-velocity 40mm grenades
  • 60mm, 81mm, and 120mm mortars
  • shoulder-launched munitions
  • 120mm tank rounds
  • 155mm artillery rounds

The training rounds should, of course, meet current performance standards, and the technology should be transferable to uses outside of military ones. Hopeful contractors have until Feb. 8 to turn in their biodegradable bullets proposals.

If you’re surprised about the DoD’s concern for the environment, consider a report the department sent to Congress in 2015 outlining the issues caused by climate change.

“The Department of Defense’s primary responsibility is to protect national security interests around the world,” officials said in a news release. “It is in this context that the department must consider the effects of climate change — such as sea level rise, shifting climate zones, and more frequent and intense severe weather events — and how these effects could impact national security.”

To see how bullets can be turned into something beautiful, check out our article “The Enemy Is a Very Good Teacher: Purple Buddha Project Transforms War into Beauty.”

Feature photo courtesy of

By Haley Shapley

Haley Shapley is based in Seattle, where recycling is just as cool as Macklemore, walking in the rain without an umbrella, and eating locally sourced food. She writes for a wide range of publications, covering everything from sustainability to fitness to travel. Read more of her work here.