The product is called AMBUstat. It uses a small fogger to create a mist with a solution that consists of water, peracetic acid, and hydrogen peroxide. Peracetic acid and hydrogen peroxide are both excellent disinfectants, and mixed together in a solution tend to be more stable and work at lower concentrations.

The same oxidation process that kills microbes also causes metal to rust. One of the challenges the NASA consulting helped EP+R overcome was to ensure the sterilizing mist wouldn’t rust or otherwise harm the ambulance engine or any of the delicate electronics on board.

Both work against organic contaminants because they are strong oxidizers—which means they easily break down into their component elements and give off an “oxygen radical” or single oxygen atom that looks to react with other atoms to form a more stable oxide. “Microbes are made up of carbon, so their chemical structure is attacked by the oxygen atoms and their cells are converted with time to harmless vapor byproducts,” like carbon dioxide and water vapor, explains Miller.

The chemical reactions take just minutes, Thompson says. To get a full clean, however, there are a few more steps: “we recommend EMTs open the drawers, the doors, their oxygen bags, and their supply bags and hang them from the horizontal rail.” That means the fog will be able to hit everything. And if the engine and air conditioning are running, it will also clean the vents and ducts.

“All you need to do is a five-minute cleanup—strip linen, throw away any visible trash, spot clean any visible matter—and run the fogger for 22 minutes. Let it sit for 15 minutes with the doors shut, and let it air out another 10 minutes,” he says: under an hour from start to finish to destroy “pretty close to 99 percent of the organisms in that space.”

The units are small—everything fits into a single backpack—and cost just $2,195 for a starter set, which includes a first case of the disinfectant fluid. Refills cost around $250 per case and provide enough for 24 to 30 treatments, depending on the size of the ambulance.

The first order came from a county in southern Texas after officials read an article in EMS World. “They sent in a blank purchase order—they didn’t know how much it would cost, but they wanted in,” says Thompson. Since then, EP+R has fulfilled orders with EMS groups in Ohio, Florida, Georgia, New York, and Canada.

To his surprise, the units are also being used beyond ambulances: in a school in Ohio, as well as in police cars and jail cells. And the interest continues to grow.

“Now we’re getting courted by an international aid group for Liberia and Sierra Leone,” two of the countries hardest hit by the 2014 Ebola epidemic, Thompson says. “I’m really hopeful. Talk about making a difference around the world.”