There’s a New Way to Sterilize Medical Devices Without Cancer-Causing Chemicals

Sterilizing medical equipment and devices is a crucial process that protects patients from harmful infections. Ironically, one of the longest-running methods of sterilizing medical equipment actually poses health risks for the people tasked with doing it.

For years, the Food and Drug Administration (FDA) has been trying to come up with better options, and they may have found one. The FDA recently recategorized a medical device sterilization method, vaporized hydrogen peroxide, as a safe, effective way to sterilize medical equipment.

The promotion of the new method is meant to encourage healthcare providers to move away from using ethylene oxide—that long-time medical equipment sterilization technique that’s been linked to health risks, including cancer.

Now that vaporized hydrogen peroxide is considered an Established Category A sterilization process by the FDA, will medicine stop relying so much on ethylene oxide?

What Is Ethylene Oxide?

You might assume that ethylene oxide (a colorless, flammable, explosive gas) is not something you regularly encounter in your daily life. But things you’re familiar with—antifreeze for your car, for example—exist because of the sweet-smelling gas.

Ethylene oxide is not something you want to spend a lot of time around. Exposure to the gas can cause eye pain, sore throat, difficulty breathing, and blurred vision, along with dizziness, nausea, headache, convulsions, blisters, vomiting, and coughing.

On top of those side effects, animal studies and lab research have shown that the gas is carcinogenic. Jamie Alan, PhD, an associate professor of pharmacology and toxicology at Michigan State University, told Verywell that “ethylene oxide can cause cancer when inhaled.”

According to the National Cancer Institute, the DNA-damaging ability of ethylene oxide makes it great for sterilization, but at the same time, is also why it could cause cancer.

Why Do Providers Use Ethylene Oxide If It’s Dangerous?

Even with the risks to human health, ethylene oxide is still the most commonly used sterilization method for medical devices in the United States. More than 20 billion devices are sterilized with ethylene oxide—about 50% of devices that need sterilization.

Keeping medical equipment and devices safe is critical for patient safety. However, finding a way to do the job without damaging the equipment has proven challenging.

Since the 1950s, the ethylene oxide method has worked well for sterilizing many medical devices, such as those made from plastic, resin, metal, or glass, without damaging the material. It’s also useful for items that have many layers of packaging or hard-to-reach places, like catheters.

However, John Sellick, DO, an infectious disease expert and professor of medicine at the University at Buffalo SUNY, told Verywell that ethylene oxide is actually “a very inefficient method of sterilization”—in part because it’s risky to work with. “You have to ventilate the chamber a lot because it’s carcinogenic, and you have to flush it out as well.”

The health risks of using ethylene oxide for sterilization are mostly to the person who is doing the task or running the sterilization equipment, added Alan. “By the time the items are sterilized, there is very little residual ethylene oxide in the vapor form.”

Still, it’s a concerning problem. After several massive leaks of ethylene oxide gas at plants in the U.S. in 2023, the FDA has been trying to find new, safer (but still effective) sterilization methods for medical equipment. They’ve teamed up with the CDC, OSHA, and EPA to try to find a solution.

That’s where vaporized hydrogen peroxide could come in.

What Is Vaporized Hydrogen Peroxide?

Vaporized hydrogen peroxide “is literally hydrogen peroxide in a vapor form,” said Alan. It’s an antimicrobial that targets viruses, bacteria, fungi, and spores—all things that you don’t want on medical equipment where they could spread to patients.

The devices can be put into a chamber where they get exposed to vaporized hydrogen peroxide and sterilized in less than an hour. The process creates byproducts—water vapor and oxygen—that are nontoxic to humans. That safer process also makes the job more efficient for workers because they won’t have to air the chamber when the sterilization is done. They’ll also be able to handle the equipment safely after it’s been sterilized.

Not only is it safer for humans, but vaporized hydrogen peroxide can inactivate or kill potentially harmful microorganisms without damaging the equipment it’s sterilizing.

Will Vaporized Hydrogen Peroxide Replace Ethylene Oxide?

Vaporized hydrogen peroxide can sterilize more than 95% of medical devices, including materials and devices that can’t tolerate high temperatures and humidity (e.g., certain plastics, electrical devices, and corrosion-susceptible metal alloys). It’s used on things like pre-filled syringes, needles, and implanted devices. But you probably won’t see it at your annual physical.

“These are not the kinds of things that primary care doctors and dentists are using,” Sellick said. Vaporized hydrogen peroxide equipment consists of “large, bulky machines.”

According to Sellick, most healthcare providers and dentists use steam sterilizers in their offices.

“Everyone is trying to get away from using ethylene oxide,” he said.

With that goal in mind, the FDA’s promotion of an alternative could be a breath of fresh air for providers looking to make a clean break from the method.