Everyone loves the party game/icebreaker “two truths and a lie.”

During 2019, several medical supply sterilization plants closed because of fears related to a chemical they use known as ethylene oxide. If you suspect that these closures exacerbated COVID-19-related shortages, you are correct. Let’s see what else you might know about ethylene oxide.

Can you identify which of the following is NOT true about ethylene oxide?

A. Ethylene oxide is a gas that naturally forms in the human body.
B. Researchers at the Environmental Protection Agency (EPA) developed a reasonable safety assessment for ethylene oxide that helps the public understand the risks.
C. The levels of ethylene oxide measured in the air around medical sterilization plants are not alarming.

A.  True!  Ethylene oxide is a gas that naturally enters air from vegetation, manure, volcanic eruptions, waterlogged soil, and combustion related to traffic, smoking, fires, and many other sources. Humans inhale some, but it’s also naturally formed inside the human body by our metabolic processes, and we release it as waste products. According to EPA, the human body is well equipped to safely manage ethylene oxide formed in body or inhaled, releasing it “fairly quickly,” with levels falling by “50% every 42 minutes.”

Ethylene oxide has many valuable commercial uses. It is used to sterilize medical supplies—everything from medical devices to bandages to disposable masks—and it is used in the production of making shampoo, cleaners, antifreeze, and more.

B. False. While EPA regulations for ethylene oxide emissions are reasonable and ensure public health is protected, a research program at EPA known as the Integrated Risk Information System or IRIS published a faulty report that needlessly alarmed the public about the chemical’s risks. IRIS released its assessment of ethylene oxide in 2016, setting an excessively stringent safety guideline at or 0.1 parts per trillion or 100 parts per quadrillion. Supposedly, people exposed to ethylene oxide above this minuscule level could have elevated cancer risks.

But considering exposures from natural sources and background levels, the IRIS figure is obviously way off the mark. The human body alone produces ethylene oxide at a level that is 19,000 times higher than IRIS’s number of 0.1 parts per trillion. IRIS’s estimate is also 1,000 to 2,000 times lower than the background levels reportedly found in urban air around the nation, which the U.S. EPA data indicate is about 0.1-0.2 parts per billion. An American Chemistry Council analysis points out: “Thus, if the EO IRIS Assessment is to be believed, normal human metabolism and/or breathing ambient air is sufficient to cause cancer.”

C. True.  Because of the panic that IRIS created, EPA took measurements of ethylene oxide in the air during 2018 and 2019 in and around medical sterilization plants, and the levels discovered are not alarming.  The levels found in and around these facilities are within range with background levels elsewhere. “No doubt, scientific truths are desperately needed in the public dialogue,” toxicologist Gail Charnley explains in a statement on the topic. “The most important truth being, there is no cancer threat from the tiny amounts of ethylene oxide released from these sterilization plants,” she said.

For more information see:

Misguided Activist Campaign Will Lead to Future Medical Supply Shortages

Deploy Rational Science-Based Policies for Medical Plant Sterilization