This colorless, flammable gas is a persistent threat to workers under outdated federal rules

In workplaces nationwide, countless employees devote their days to crucial tasks that make sure that hospitals operate smoothly, factories remain productive, and communities receive essential goods.

But many of these workers are being exposed to hazards that could have lasting impacts on their lives.

This danger is especially acute for thousands working in hospitals, sterilization facilities, and manufacturing companies that rely on ethylene oxide (EtO), a colorless, flammable gas typically used to decontaminate medical devices and produce a range of industrial chemicals. EtO has been recognized as carcinogenic for years. However, it remains subject to the exposure limits of the Occupational Safety and Health Administration (OSHA), which have not been meaningfully updated in decades. While these standards define the acceptable concentration of EtO to inhale, this guidance may still fall far short, since health experts have already indicated that there may be no safe level of exposure for workers. 

Since it was first produced in the U.S. in 1921, EtO has been central to the country’s medical and industrial infrastructure. Yet to this day, its drastic impacts remain largely unknown to the very workers whose labor depends on it. At its core, this transparent but highly combustible gas is extensively used to eliminate harmful microbes from delicate and heat-sensitive medical instruments, such as catheters, stents, wound dressings, and other equipment integral to general practice. In the U.S. alone, approximately 20 billion medical devices are sterilized with this chemical, making it vital in ensuring that critical tools reach hospitals safe to use on patients. What is far less visible, however, is the health cost borne by the workers handling EtO each day.

Scientific evidence demonstrates that frequent inhalation or contact with EtO can trigger the development of neurological disorders, respiratory illnesses, reproductive conditions, and a myriad of cancers, including lymphoma and malignancies of the breast, brain, connective tissue, lung, and uterus. Even the Environmental Protection Agency (EPA) has acknowledged this danger, which prompted the substance’s official classification as a human carcinogen in December 2016. Yet the threat persists and continues to compromise the health of thousands of sterilizing workers nationwide.

In part, this is because OSHA’s permissible exposure limits have not been sufficiently revised since 1984. Under the rule, commercial sterilizers and various pharmaceutical and manufacturing firms may legally continue to use this chemical, all while adhering to an occupational exposure standard of just 1 part per million in the air. But though these operations may be technically compliant, modern science shows that even this minimal amount can substantially increase the risk of cancer and other serious illnesses.

In addition to the outdated exposure limit, OSHA has also required employers to implement periodic air sampling and basic engineering controls, as well as ensure the use of personal protective equipment, medical surveillance, and recordkeeping, among other measures. Yet even with all these requirements, the policy still falls short of safeguarding workers—especially as it does not mandate real-time monitoring or the requirement to provide immediate assistance to those impacted. The contrast is stark. What is legal under outdated standards is far from safe in practice—thereby creating a regulatory gap that jeopardizes the health of thousands of employees.

This glaring disconnect between modern toxicology and outdated regulations is a serious threat to workers’ daily lives and a critical national issue.

The EPA revealed that more than 80 plants across the country have documented alarming EtO concentrations, and at least 25 of these have historically increased a neighborhood’s cancer risk. Among the severely contaminated sites was Laredo, Texas’s Midwest Sterilization Corporation, where cancer risks exceeded 350 times the safety limits. Also included was Willowbrook, Illinois’s Sterigenics Willowbrook Facility, which reported estimated risks 64 times the federal benchmark. These findings make it clear that without immediate regulatory intervention, workers throughout the country will continue to face routine exposure to a potentially fatal chemical.

Addressing this regulatory gap is not optional—it is critical. OSHA must update its permissible exposure limits to align with the latest toxicological research and finally make sure that legal compliance actually protects workers from the well-documented risks of EtO. Likewise, facilities should be mandated to strictly implement real-time monitoring and state-of-the-art ventilation systems so that exposure is continuously tracked and promptly controlled. Employees who handle this chemical must also undergo long-term medical surveillance to enable early detection of any health effects and provide timely and appropriate treatment. Equally important is fostering worker transparency through clear notices, comprehensive training, and accessible information on exposure levels.

By enacting these crucial measures, OSHA can bridge the disconcerting gap between regulatory compliance and real-world safety, and finally protect the thousands of Americans whose daily work keeps hospitals, factories, and communities running.

Editorial Team:
Tina Vasquez, Lead Editor
Lara Witt, Top Editor
Rashmee Kumar, Copy Editor