A scientific advisory panel to the EPA is convening today to evalute the environmental watchdog’s determination that a common medical device sterilizer, ethylene oxide, is carcinogenic.
If the panel confirms that assessment, medtech companies warn, it could disrupt the supply chain for their lifesaving products.
Ethylene oxide is mostly used to make ethylene glycol, a key ingredient in antifreezes, polyester fibers and a plastic used in building materials and bottles. But it’s also used to sterilize medical instruments – Boston Scientific (NYSE:BSX) told the agency that it uses the compound to sterilize some 70% of its devices – and is vital because of its ability to sterilize hard-to-reach crevices.
The EPA’s current draft "integrated risk information system" concludes that ethylene oxide can cause cancer when inhaled. The last time the agency issued a final assessment was in 1985, when it decided that the compound is a probable carcinogen.
"Boston Scientific uses EO to sterilize 70% of its devices manufactured globally, and restricting the use of EO as a viable sterilization method would severely impact the availability of approximately 32 million devices sterilized annually, many of which are life-saving," the company wrote in a letter to the advisory panel. "Adopting an overly conservative estimate of potential risks from exposure to EO, as has been proposed, would disrupt the availability of medical devices and equipment to healthcare providers, and seriously impair their ability to serve their patients. Given the importance of EO sterilization to preserve and promote public health, it is particularly important in this case that the CAAC not rely on models or exposure estimates that exaggerate potential cancer risk."
Boston Scientific said the chemical is the "only option" for sterilizing many medical devices "specifically designed with materials that are tolerant of EO."
"Other sterilization methods, such as e-beam, steam, or gamma radiation, could cause device damage and render them inoperable in a clinical setting. Furthermore, in many cases, EO is the only method of sterilization that can safely and effectively sterilize all parts of the device," the company wrote. "EO, therefore, is critical to the delivery of safe and sterile medical devices to the clinical community. Without it, or reduction in occupational exposure limits may result in the potential for severe risk of infection or, alternatively, inability to manufacture products that are necessary for patient care. In fact, a change in the requirements for sterilization technology may introduce risks of product integrity, toxicological safety and biological infection that may exceed the risks of EO sterilization itself."
The human body naturally produces some ethylene oxide, but the risk estimate in the EPA assessment is higher than endogenous levels in humans and in natural background levels, according to the Ethylene Oxide Sterilization Assn.
"We believe that the current assessment results in the risk of EO being inappropriately magnified by more than 1,500-fold," the association told the advisory panel.
"Ethylene oxide has been used for over 50 years as the primary method for sterilization of heat and moisture sensitive medical instruments. It is the most efficient sterilant for these medical devices because of its ability to penetrate complex geometries such as lumened devices. It is also gentler on device materials compared to oxidative sterilants such as hydrogen peroxide, helping to extend device life and reduce the need for repairs," 3M wrote. "The combination of the penetration ability and superior materials compatibility makes EO critical for sterilization of intricate devices while assuring the most cost-effective sterilant in the health care setting. Recent incidences with medical device reprocessing reveal risks associated with improperly sterilizing medical instruments. With the increased focus on reducing health care associated infections and lower overall health care costs, EO is an important option that needs to be available to health care facilities."
Some 20 billion medical devices are sterilized each year with EO in the U.S. alone, Steris said, calling the compound "critical in the safe delivery of sterile devices and medical care."