Following an evaluation of the carcinogenic risks posed by ethylene oxide (EtO), which the EPA released in 2016, and a follow-up National Air Toxics Assessment (NATA) for EtO, the EPA has decided that the health risks posed by EtO air emissions are “significantly higher” than previously believed. Accordingly, the Agency is considering revisions to several sets of regulations to lower the risk. One such action is an advanced notice of proposed rulemaking (ANPR) that explains the existing National Emissions Standards for Hazardous Air Pollutants (NESHAP) governing sterilization facilities using EtO and requests information from the public on how the NESHAP should be amended.

The NESHAP applies to both major and small (area) sources that use at least 1 ton of EtO in sterilization or fumigation operations in each 12-month period. The EPA estimates that there are 108 EtO sterilization facilities, 35 of which are owned by small businesses.

Alternative to steam

EtO is commonly used by companies to sterilize medical equipment that may be damaged by steam sterilization. The Food and Drug Administration reports that about 50 percent of all sterile medical devices in the United States—about 20 billion devices a year—are sterilized with EtO. Types of devices sterilized with EtO range from those used in general healthcare practices (for example, wound dressings) to more specialized devices used to treat specific areas of the body (for example, stents).

Explosions in the 1990s

In 1994, the EPA issued its initial NESHAP for EtO sterilization facilities. The rule required that major sources of EtO emissions meet limits determined by the maximum achievable control technology (MACT), while area sources meet limits determined by the generally available control technology (GACT). In the 1990s, there were multiple explosions at EtO sterilization facilities, and the EPA suspended the NESHAP for several years. Most of the rule was later reinstated, although requirements for chamber exhaust vents (CEVs), found to be the location of most of the explosions, remained suspended. In 2006, the Agency completed a residual risk and technology review of the EtO sterilization NESHAP and made no changes as a result of the review.

The use of EtO for sterilization has become particularly controversial in Illinois. The state recently issued its own regulations, which the Illinois EPA says require the strongest EtO emissions controls in the nation. Bills have been introduced in the Illinois Legislature to ban the use of EtO for sterilization.

Data sought

The EPA concedes that amending the NESHAP to better address risks to human health is a complex undertaking. The Agency says it met with 12 different EtO trade associations, air pollution control device manufacturers, industry representatives, and other government agencies to better understand sterilization processes and current control technologies. Even with the outreach, the EPA says the ANPR is needed to fill information gaps prior to any future rulemaking activity.

Items in the ANPR for which more information is sought include the following:

• Usage data for individual facilities.
• Fugitive emissions. The magnitude of fugitive emissions from the industry is not well characterized
• Industrywide use of permanent total enclosures to capture EtO emissions.
• Use of pollution-prevention and other operational practices (e.g., leak detection and repair and reducing the amount of EtO injected into the sterilization chamber).
• Reconsideration of CEV requirements. Some facilities have implemented changes to ensure the lower explosive limit (LEL) in the CEV is not exceeded. The EPA is seeking information on the controls being used and their effectiveness, costs, and feasibility.
• Other information requests address issues such as EtO emissions monitoring and types of sterilization facilities (e.g., single-item sterilization facilities vs. combination sterilization facilities).

Small businesses

Given the high percentage of small EtO facilities, the EPA is also requesting comment on the extent to which facilities owned by small businesses differ operationally from facilities operated by larger businesses, including whether emissions profiles differ consistently. The Agency says it intends to convene a Small Business Advocacy Review (SBAR) Panel before taking any significant regulatory action.