Ethylene Oxide

Chapter 296-855, WAC

Effective Date: 01/01/06

Helpful Tools

WAC 296-855-400

Exposure Control

For printing

Your Responsibility:

To protect employees from exposure to ethylene oxide (EtO) by using feasible exposure controls and appropriate respirators


• These sections apply when employee exposure monitoring results are above either of the following permissible exposure limits (PELs):

– The 8-hour time-weighted average (TWA8) of 1 part per million (ppm)


– The 15-minute short-term exposure limit (STEL) of 5 ppm.

Exposure control plan

WAC 296-855-40010

Exposure controls

WAC 296-855-40030


WAC 296-855-40040

WAC 296-855-40010

Exposure control plan

You must

• Establish and implement a written exposure control plan to reduce employee exposure to EtO below both TWA8 and the STEL by the use of feasible exposure controls. Include at least the following in your plan:

– A schedule for periodic leak detection surveys

– Make sure employee rotation isn't included as a method to control employee exposure.

• Establish a written plan for emergency situations for each work area where there is a possibility of an emergency from a release of EtO. The plan must include, at a minimum:

– Emergency escape:

• Procedures

• Route assignments

– Emergency evacuation plans and procedures to account for all employees after emergency evacuation has been completed

– Procedures to be followed by employees who remain to operate critical plant operations before they evacuate

– Requirements for the use of respiratory protection as required in WAC 296-855-40040

– Rescue and medical duties for those employees who will perform them

– The preferred means of reporting fires and other emergencies

– Names or regular job titles of persons or departments who can be contacted for further information or explanation of duties under the plan.

• Establish an employee alarm system that meets the requirements of Employee alarm systems, WAC 296-800-31070 in the Safety and Health Core Rules.

– The employee alarm system must be distinctive and recognizable as a signal to perform actions designated under the emergency response plan.

• Review your exposure control plan at least every 12 months and update as needed to reflect your current workplace conditions.

• Provide a copy of your exposure control plan to affected employees and their designated representatives, when they ask to review or copy it.

WAC 296-855-40030

Exposure controls


The use of an employee rotation schedule to control employee exposure to ethylene oxide (EtO) is prohibited.

Respirators and other personal protective equipment (PPE) aren't exposure controls.

You must

• Use feasible exposure controls to:

– Reduce exposure to, or below, the permissible exposure limit (PELs)


– To reduce exposure to the lowest achievable level above the PELs

WAC 296-855-40040



    • The requirements in this section are in addition to the requirements found in another chapter, Respirators, chapter 296-842 WAC.
    • Medical evaluations meeting all requirements of WAC 296-855-30030, will fulfill the medical evaluation requirement found in another chapter, Respirators, chapter 296-842 WAC.

You must

• Provide each employee with an appropriate respirator that complies with the requirements of this section, and require that employees use them in circumstances where exposure is above either PEL, such as when:

– Feasible exposure controls are being put in place.

– Employees conduct work operations such as maintenance and repair activities or vessel cleaning for which exposure controls aren't feasible.

– Feasible exposure controls don't reduce exposures to or below the PELs.

– Employees are responding to emergencies.

• Ensure all respirator use is accompanied by eye protection either through the use of full-facepiece respirators, hoods, or chemical goggles.

• Develop, implement, and maintain a respirator program that meets the requirements of another chapter, Respirators, Chapter 296-842 WAC, which covers each employee required by this chapter to
use a respirator.

– Select and provide to employees appropriate respirators according to this section and WAC 296-842-13005 in the respirator rule.


– Limit selection and use of respirators, including escape respirators, to those with a full-facepiece or another type of respirator providing eye protection. This is necessary to prevent eye irritation or injury from EtO exposure.


– Equip full-facepiece air-purifying respirators, including escape respirators, with a front- or back-mounted cansiter certified for protection against ethylene oxide.


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