The use of a carcinogen by medical sterilization company Sterigenics at its Cobb County plant in the Smyrna area has raised concerns and questions since it was publicly revealed in July that there are elevated cancer risks in the surrounding neighborhoods.

The following information, detailing operations at the Cobb Sterigenics plant at 2971 Olympic Industrial Drive, was provided by the company’s president, Philip Macnabb, who spoke publicly at a Cobb County Board of Commissioners’ work session in Marietta on Aug. 26.

Additional information comes from the state and federal agencies that Sterigenics has self-reported its annual ethylene oxide emissions to, including the Georgia Environmental Protection Division and the U.S. Environmental Protection Agency.

Sterigenics and its Cobb County plant:

Sterigenics is a global company that sterilizes medical equipment in over a dozen different countries. The plant in Cobb County has been operating since 1972 and is one of 47 Sterigenics facilities, where over a million pieces of medical equipment are sterilized every day for use in hospitals and clinics. The plant operates 24 hours a day, seven days a week with around 30 employees and captures around 99% of the ethylene oxide it uses through an emissions control system. Currently about 260 pounds of ethylene oxide in gas form is emitted from the plant every year. Once additional emissions controls have been installed, by mid-October, the plant’s ethylene oxide emissions should be down to about 40 pounds a year. There are over 40 monitors in the plant, determining either the explosiveness of the ethylene oxide in use or its concentrations within the facility to protect workers from injury and exposure.

The sterilization process:

Sterigenics uses three methods of sterilization: ethylene oxide, electron beam processing and gamma irradiation. The Cobb plant is one of 19 Sterigenics facilities that uses ethylene oxide. The plant receives prepackaged medical equipment in boxes loaded onto pallets and shrink-wrapped. About 30 pallets at a time are loaded, still shrink-wrapped and untouched, into the plant’s sterilization chambers, where a vacuum is drawn and ethylene oxide and nitrogen is piped in.

The product sits in the ethylene oxide-filled chamber for 10 to 12 hours before the toxic air in the chamber is sucked through an emissions control system. The sterilized product is then moved into an aeration room, where any residual ethylene oxide can leach out and be sucked through the emissions controls. Once the product has been in the aeration room for about 48 hours, it leaves the plant for distribution and use in medical facilities. The entire sterilization process at the plant takes about four days.

Why ethylene oxide?:

Sterigenics claims some medical equipment, including surgical packs and vascular catheters, cannot be sterilized properly by electron beam processing or gamma irradiation, so ethylene oxide is the company’s only viable option. Some of this equipment is made from materials that are degraded or compromised by gamma irradiation, and electron beam processing is unable to penetrate through some of the equipment packaging so it, too, is ineffective.

Many of the products Sterigenics claims can only be sterilized with ethylene oxide are single-use medical devices that get discarded after they’ve been unpackaged and used. Much of the product sterilized in the Cobb plant is distributed and used in Georgia and some is transported out of state. Sterigenics claims around half of all the single-use medical devices in the United States are sterilized with ethylene oxide.

The U.S. Food and Drug Administration’s website states ethylene oxide may be the only method that effectively sterilizes and does not damage many medical devices, and that half of all the sterilized medical devices in the country are sterilized with ethylene oxide.

“Medical devices made from certain polymers (plastic or resin), metals, or glass, or that have multiple layers of packaging or hard-to-reach places (for example, catheters) are likely to be sterilized with ethylene oxide,” the FDA website states. “The types of devices that are sterilized with ethylene oxide range from devices used in general health care practices (for example, wound dressings) to more specialized devices used to treat specific areas of the body (for example, stents).”

Annual ethylene oxide emissions:

Sterigenics has self-reported the majority of its annual ethylene oxide emissions from its Cobb plant but several gaps in the data remain. The first publicly available emissions data is from 1987, when almost 90,000 pounds of ethylene oxide in gas form was released from the facility. Since then annual emissions have varied.

Emissions are known for 25 of the past 32 years, totaling 213,808 pounds and showing an average annual release of just over 8,500 pounds.

Here are Sterigenics’ self-reported annual emissions (in pounds) of ethylene oxide from its Cobb County plant:

2018 — 252

2017 — 227

2016 — 226

2015 — 3,574

2014 — 3,189

2013 — 3,312

2012 — 3,420

2011 — 3,008

2010 — 2,736

2009 — 2,483

2008 — 2,661

2007 — 2,784

2006 — 2,616

2005 — 2,930

2004 — 3,179

2003 — 2,558

2002 — 2,211

2001 — 6,118

2000 — 4,946

1999 — 10,900

1998 — 15,560

1997 — 7,170

1996 — 8,160

1995 — 6,971

1994 — unknown

1993 — unknown

1992 — unknown

1991 — unknown

1990 — unknown

1989 — unknown

1988 — 23,084

1987 — 89,760

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