Honeywell Stops Taking Orders for Oxyfume Ethylene Oxide Sterilants

Honeywell announced in August 2012 that it would discontinue production of the Oxyfume ethylene oxide (EtO) sterilant gas cylinders because of Clean Air Act regulations from the EPA banning the sales and use of most HCFC based products like Oxyfume in the end of 2014.

On March 15th, Honeywell announced that they would no longer receive orders for Oxyfume after March 31st 2013 and that Oxyfume 2002 and Oxyfume 2000 cylinders should be sent to Honeywell for recycling until production ceases later this year. Cylinders of Oxyfume 12, a CFC-based product phased out in 1995, cannot be received by Honeywell and current and former customers should contact Honeywell for information on how to handle these cylinders.

Ethylene oxide used to be the dominant low temperature sterilant in healthcare and ethylene oxide blends were the primary means of delivering EtO. The blends were used because ethylene oxide is a flammable/explosive gas with a lower explosive limit of 3% v/v with mixtures being explosive up to 100%. Ethylene oxide explosions can cause major damage, as happened to Sterigenics in 2004; and so the ethylene oxide is diluted with an inert gas to make the mixture non flammable. Both carbon dioxide and chloroflorocarbons (CFCs) were used as the inert gas. Honeywell's Oxyfume 12 contained 12% EtO and 88% CFC-12, (Dichlorodifluoromethane) which was banned under the Montreal Protocol, its manufacture was banned in the United States along with many other countries in 1996 due to concerns about damage to the ozone layer.

CFCs were replaced with hydrochloroflurocarbons (HCFCs) and Honeywell introduced the oxyfume 2000 which contained 8.6% EtO in 91.4% HCFC-124 (Chlorotetrafluoroethane) and the Oxyfume 2002 which contained 10% EtO, 27% HCFC-22 (Chlorodifluoromethane) and 63% HCFC-124. The switch to the HCFCs was a temporary measure and they in turn are being phased out under the revised Montreal Agreement.

Market forces are also acting against the EtO blends which held a dominant market position before the 1990s. Honeywell estimates that more than 70 percent of hospitals in the United States have used Oxyfume in their sterilization facilities over the last 40 years. In 1993 Advanced Sterilization Products (ASP) launched its Sterrad hydrogen peroxide sterilizer which offered much shorter cycle times compared to the ~ 15 hours required for EtO sterilization and aeration and ASP's marketing emphasized the carcinogenic properties of EtO (even though the OSHA permissible exposure limits for EtO and hydrogen peroxide vapor are the same 1 ppm time weighted average over 8 hours).

The Sterrad system offered significant safety features, particularly by operating under reduced pressure (leaks will be in not out) and newer EtO sterilizers were introduced by 3M and Steris Corporation that also operated at reduced pressure and used single use cartridges. Both of these measures served to reduce employee exposure to EtO compared to the older pressurized systems. The single use cartridges uses a small quantity (100 - 170g) of 100% EtO and so do not use the HCFC blends and avoid the need to run gas lines and change EtO gas cylinders.

There has been a lot of confusion over the years about whether EtO was being phased out. It is not! It is the CFC and HCFC blend gases that are being phased our to protect the stratospheric ozone layer. EtO is still the major gas sterilant used by medical device manufacturers because it can be used for sterilization of almost all medical devices including plastic and heat sensitive materials.

EtO is not going away; the world production of EtO was 19 million tonnes in 2008 and 18 million tonnes in 2007 which places EtO as the 14th most produced organic chemical; and the amount of EtO used for sterilization is a minuscule fraction of this production. Even though EtO use in healthcare has dropped in the last two decades, there are still many hospitals that use EtO as for low temperature sterilization and it is likely that EtO will continue to be an important low temperature sterilant gas for the foreseeable future.

The Dangers of Formaldehyde Exposure in Beauty Salons and Healthcare

Formaldehyde is one the most widely used 'bad boys' of the chemical world, to use an expression favored by ChemDAQ's CFO. Formaldehyde is used, across many different industries, ranging from the production of amino (e.g. urea-formaldehyde polymers (glues & adhesives), melamine-formaldehyde (thermosetting rigid plastics), phenolic, and polyacetyl resins (engineering plastics), wood products, plastics, fertilizers and foam insulation; as a textile finish, preservative, stabilizer, and a disinfectant" [Merck Index, 12th Ed] to name just a few.

Formaldehyde is useful because of the wide range of chemical reactions in which it can participate. It is a strong reducing agent, it water soluble (formalin solution) and most importantly it is an alkylating agent and binds amine groups, and aromatic rings. These last properties are what makes formaldehyde useful in healthcare. Formaldehyde solution (formalin) is used as a fixative because it can cross link proteins and so fix tissue samples. It does the same thing in living organisms and so formaldehyde is strongly antimicrobial finding use as a disinfectant and sterilant (e.g. low temperature steam formaldehyde sterilization)

As with any chemical sterilant, formaldehyde poses significant risks to anyone exposed to it. Formaldehyde is a known carcinogen and causes cancer of the nasopharynx & sinonasal cancer and leukaemia. (IARC) and National Toxicology Program). It is also a sensitizer and a primary irritant [ATSDR].

These dangers are well known and OSHA has promulgated a standard for formaldehyde (29 CFR 1910.1048) and has set permissible exposure limits of 0.75 ppm (8 Hour time weighted average (TWA), and 2 ppm as a 15 minute TWA short term exposure level (STEL).

Formaldehyde is a very useful chemical, but it is often used in environments that are not set-up to handle chemical exposures. For example formaldehyde is often used in hair straightening formulations (similar chemical mechanism to the tissue fixative) and in the last couple years OSHA has targetted beauty salons, issued a press release a hazard alert and even created a website dedicated to the dangers of formaldehyde exposure in addition to citing them for violations of OSHA standards. However, most beauty salons have neither the equipment nor the training to protect their workers to the levels required by the OSHA standard.

The product manufacturers have been of marginal help, sometimes inadvertently leaving the formaldehyde off the product label ingredients, claiming that the levels are so low as to be safe or using one of the other chemical names for formaldehyde such as methylene glycol that is less easily recognized by those with limited chemical training. A much safer approach for both the salon workers and of course their customers would be to eliminate all formaldehyde from these applications.

Formaldehyde solution was widely used as a disinfectant and sterilant in healthcare, but in the US it has largely been replaced by glutaraldehyde as a liquid sterilant/high level disinfectant. Low temperature steam formaldehyde is still widely used in European and other countries in dedicated LTSF sterilizers. In the US formaldehyde is primarily used in health care as a tissue preservative and as a major component of embalming fluids.

Formaldehyde can be used safely provided that adequate safety precautions are taken. Employers using formaldehyde must provide the OSHA required Hazard Communication training for all workers using hazardous chemicals (29 CFR 1910.1200) as well as training on the formaldehyde specific standard.

Employers must ensure that their people are not exposed to formaldehyde concentrations over the OSHA PELs. Employers who use formaldehyde can do this by use of adequate engineering controls to prevent exposure, continuous gas monitors for formaldehyde to ensure that the other safety devices are sufficiently protective and provide warning to workers in something fails, suitable personal protective equipment and training on how to handle formaldehyde safety and what to do it things go wrong. These are similar to the requirements as for other sterilant and high level disinfectant chemicals such as ethylene oxide, hydrogen peroxide, peracetic acid, o-phthalaldehyde and glutaraldehyde.

ChemDAQ Steri-Trac® Monitors Saves Workers from Leaking EtO Sterilizer

We received a call from a hospital customer who said that over this past weekend, they had an ethylene oxide leak from one of their sterilizers and without the ChemDAQ Steri-Trac monitors no one would have known.

The leak arose because of an electrical fault in the scrubber and the entire exhaust system shut down, but there was no indication of this happening on any of their screens. The sterilizer was completing the cycle and when they opened the door, the ChemDAQ monitor alarms sounded and they were getting readings up to 50 ppm.

They immediately evacuated the department and were relieved they could see what was happening on the remote video display (RVD) outside the department.

If there had been no monitor they would have not known about the EtO leak and their people may well have been exposed to high concentrations of EtO.

Calls like this show the value of the ChemDAQ system and reminds us at ChemDAQ that our products are designed to save lives.

It also shows that even the best designed sterilization equipment can sometimes fail and that it is important to have a continuous gas monitoring system installed that will provide an immediate alert if there is a leak.

An automated alert is essential with ethylene oxide since EtO has no odor below about 400 ppm far above the OSHA permissible exposure limit of 1 ppm (8 hr time weighted average (TWA)) and the OSHA Excursion limit/15 minute TWA short term exposure limit of 5 ppm [29 CFR 1910.1047].

If anyone would like to share their story about sterilant gas leaks and/or detection of sterilant gases with continuous monitors, please fill out the comment box below.