Standard Operating Procedure (SOP)

PURPOSE
The purpose is to use ethylene oxide as a sterilant at Wake Forest University Health Sciences.

SCOPE
The scope of ethylene oxide is to use in a laboratory or clinic environment.

HEALTH, SAFETY, ENVIRONMENTAL INFORMATION

Physical Hazards

·         Flammable and explosive

·         Reacts with water, evolving heat. In closed containers, reaction may be self accelerating, resulting in container rupture.

·         Contamination with acidic or basic materials accelerates reactions with water.

·         Contamination of pure ETO with acidic, or basic materials, metal oxides, metal chlorides, or active catalyst surfaces may cause explosive polymerization.

·         May polymerize violently in container if exposed to heat.

Health Hazards

• Considered a suspect human carcinogen.
• Liquid ETO and ETO/water solutions:

o        Are extremely irritating to skin and eyes

o        Can cause blistering and severe damage

o        Easily penetrate cloth, leather and some types of rubber. Leather cannot be decontaminated.

o        Water contaminated with ETO evolves into ETO vapor and can be a source of exposure.

• ETO vapor can be absorbed by wet or sweaty skin, with potential for serious chemical burns.

·         Odor thresholds are much greater than permissible exposure limits; overexposure occurs before the odor can be detected.

·         Inhalation of ETO vapors:

o        Causes irritation of exposed surfaces (eyes, nose, throat, and lungs)

o        Potential effects on central nervous system include drowsiness, nausea, convulsions and limb weakness

Chemical burn resulting from low concentration of EO in water.

Personal Protective Equipment

• Eye Protection

o        Safety glasses, goggles or face shields shall be worn during operations in which ethylene oxide might contact the eyes (e.g., through vapors or splashes of solution).

o        Ordinary (street) prescription glasses do not provide adequate protection.  Adequate safety glasses must meet the requirements of the Practice for Occupational Education Eye and Face Protection (ANSI Z87.1-1989) and must be equipped with side shields. 

o        Contact lenses shall not be worn if the potential exist for acetaldehyde exposure.

·         Hand Protection

o        NIOSH recommends Barricade, Responder, Trellchem, or Tychem Gloves for 8-hour exposures.

o        NIOSH recommends butyl rubber, Teflon, or PE/EVA (Silvershield) Gloves for 4-hour exposures.

·         Lab Coats, etc.

o        Lab coat, closed-toe shoes and long-sleeved clothing shall be worn when handling ethylene oxide. Protective clothing shall be worn to prevent any possibility of skin contact with ethylene oxide.

·         Safety Shower / Eye Wash

o        Where the eyes or body of any person may be exposed to acetaldehyde, suitable facilities for quick drench or flushing of the eyes and body shall be provided within the work area for immediate emergency use. 

o        Bottle type eyewash stations are not acceptable.

Designated Area for Use and Containment Devices

The regulated area of A1 is Room 4. 

This regulated area is marked and access limited. Warning signs are posted around regulated area stating:

Special Handling Procedures and Storage Requirements

Ethylene oxide sterilizer must be used in conjunction with a functioning chemical exhaust hood and ETO neutralizing system.

Waste Disposal

Full containers of ethylene oxide must be disposed of according to WFUHS EH&S Hazardous Waste Program.

Decontamination of Equipment and Area

Contact WFUHS EH&S at 716-1221 for decontamination information.

Accidental Releases and Spills Procedures oxide spill or release.

• Accidental Releases

Accidental releases of ETO may occur from several sources, including glass ampules, cartridges, sterilizer discharge lines, and ETO supply cylinders. Glass ampules generally contain 4 to 18 g of ETO, and single-dose cartridges usually contain 67, 100, or 134 g of ETO, depending on their size. An 8.8-ft³ sterilizer uses a mixture of ETO (12% by weight) and dichlorodifluoromethane, and it discharges approximately 150 g of ETO into the drain during each purge cycle.  A typical large supply cylinder for the 12:88 gas mixture contains 7,000g of ETO.

Because the odor of ETO cannot generally be detected below approximately 700ppm [Clayton and Clayton 1978], workers can be exposed to high concentrations of this compound without knowing it.  A relatively small quantity of ETO in an average room can create concentrations that are many times the exposure limit.

DESCRIPTION OF PROCESS

Ethylene oxide (ETO) is used as a sterilant in hospitals and laboratories.  Sterilization results from a reaction between ETO and cell nucleic acids, disrupting protein synthesis.  It is used for equipment or devices that cannot tolerate heat sterilization.