The solution to the ethylene oxide crisis

More than 20 billion of the medical devices sold in the US every year are sterilized with ethylene oxide. As important as it is to the healthcare system, however, the gas is a threat to human health in and around many of the sites that use it, a fact that has already forced numerous closures. PAMA’s facility is different. The Canadian company has developed a unique, environmentally friendly EtO sterilization process that cuts emissions to the absolute minimum while saving clients time and money.


thylene oxide (EtO) – the gas used to sterilize around half of all medical devices – is the lifeblood of the healthcare supply chain. Without it, doctors and nurses wouldn’t have the sterile tools they need to treat and care for patients. However, if it’s mishandled, EtO, like any hazardous gas, can cause harm to people and the environment.

In 2019, that contradiction began to bite. Pollution concerns forced the closures of multiple US EtO sterilization facilities, sliding the country towards a potentially life-threatening deficit in its supply of medical devices and surgical tools. Despite resistance from sterilizers and the chemical industry, the EPA has since imposed new reporting requirements on 29 major facilities. It is also planning to propose an addition to the Clean Air Act requiring commercial sterilizers to tightly control their EtO emissions.

Things have changed quickly since 2016, when the EPA first classified EtO as a carcinogen. Before then, it was only lightly regulated – and now much of the industry is struggling to adapt. But some of it is thriving. A quick glance north of the border is enough to show what a modern, safe, eco-efficient and economic process can achieve.

From days to hours

In Canada in 2019, Quebec-based company PAMA Manufacturing and Sterilization was installing its in-house EtO sterilization system. As executive director and engineer Rasha Al Hashimi recalls, the troubling news from the US gave the team reason to pause and ask, “What can we optimize here? What can we do to make things safer?” and “Is there a possibility to reduce EtO concentration while making sure the process is still sterile and conforms to ISO 11135?“

In short: yes. What PAMA realized is that there’s no need for contradiction or compromise at all. Its innovations have made sterilization cheaper, faster and more convenient for the healthcare system – and healthier for the planet.

Whereas the industry standard ethylene oxide concentration for sterilization is around 800 mg per litre, PAMA’s fully automated and enclosed process requires less than 450 mg. Largely on account of this reduction, the company can complete an entire sterilization cycle in a mere 14 hours – making it considerably faster than even the initial preconditioning phase of a traditional process, which can sometimes take two to three days. And that’s only the beginning: in most industry systems, after preconditioning, a load has to spend a number of hours in sterilization, a further 36 to 72 in aeration, and a full week being incubated with biological indicators to ensure the process actually worked.

The benefits of saving so much time are manifold. Not only is a costly bottleneck removed, but PAMA’s clients don’t need to stockpile as much equipment to make up for slow sterilization rates, and PAMA can get through far higher volumes than other facilities of the same size. “People come to us because our turnover time is fast, and we have the capacity to respond to their demands for growth,” says Al Hashimi. Helpfully, the company is ready to build new sterilizers and add further capacity with the right partners.

Clean as can be

Like PAMA’s existing infrastructure, these new sterilizers will be designed to ensure risks from EtO emissions are kept as close to zero as scientifically possible. Using less ethylene oxide is automatically better for the environment, but PAMA’s facility is designed to go “above and beyond” normal industry requirements and avoid all risk of EtO exposure. It uses a scrubber system to capture all EtO emissions and recycles the gas into ethylene glycol, which the company is working on commercializing for use in windscreen washer and airplane de-icer.

Although there is no requirement to do so in Canada, PAMA also has the ethylene oxide levels surrounding its facility regularly measured by an independent party. As such, it can continually track its environmental impacts and make sure all health and safety risks are minimized.

Do no harm

Today, as in 2019, there are no readily available alternatives to EtO for sterilizing the billions of plastic, metal, glass, packaged or intricately shaped medical devices currently treated with the gas. Heat or radiation sterilization techniques would damage them, and other methods, which are ineffective for packaged devices, are years from industrialization. At the same time, older EtO plants leak pollutants that, far from helping treat people, make them ill.

But it’s not 2019 anymore. It’s now possible to use EtO to sterilize medical devices without risking any harm to public health. As well as being more cost-effective and efficient, PAMA’s system completely removes the supply chain threat of enforced closures. If that sounds appealing, it also has spare capacity and space to grow.

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