What is ethylene oxide?

Ethylene oxide (EtO) is a flammable, colorless gas at

temperatures above 51.3 oF (10.7 oC) that smells like

ether at toxic levels. EtO is found in the production of

solvents, antifreeze, textiles, detergents, adhesives,

polyurethane foam, and pharmaceuticals. Smaller

amounts are present in fumigants, sterilants for spices

and cosmetics, as well as during hospital sterilization of

surgical equipment.

How can ethylene oxide harm workers?

In addition to eye pain and sore throat, exposure to

EtO can cause difficult breathing and blurred vision.

Exposure can also cause dizziness, nausea, headache,

convulsions, blisters and can result in vomiting and

coughing. Both human and animal studies show that

EtO is a carcinogen that may cause leukemia and other

cancers. EtO is also linked to spontaneous abortion,

genetic damage, nerve damage, peripheral paralysis,

muscle weakness, as well as impaired thinking and

memory. In liquid form, EtO can cause severe skin

irritation upon prolonged or confined contact.

What should employers know about

ethylene oxide?

Employee exposure is limited to one part EtO per

million parts of air (1 ppm) measured as an 8-hour

time-weighted average (TWA). Employee exposure may

not exceed the short-term excursion limit of 5 ppm EtO

averaged over any 15-minute sampling period. These

limits are called permissible exposure limits (PELs).

Most occupational exposures to EtO are covered by

the OSHA standard. The standard does not apply,

however, when employers can demonstrate that the

processing, use, or handling of products containing EtO

will not release airborne concentrations of EtO at or

above the standard’s action level of 0.5 ppm. The

action level is calculated as an 8-hour TWA and is the

threshold for increased compliance activities (e.g., air

monitoring, medical examinations, labeling, employee

information, and training).

For details of the requirements in OSHA’s EtO

standard for occupational exposures, see Title 29 of the

Code of Federal Regulations (CFR) Part 1910.1047.

Note: Workplaces are exempt from this standard when

objective data shows that the processing, use, or

handling of products containing EtO cannot release

airborne concentrations of EtO at or above the action

level or in excess of the excursion limit during normal

conditions.

What must employers do when exposures

exceed the standard’s permissible exposure

limits?

If employee exposures exceed either the PEL or

the excursion limit, employers must take the following

actions:

■ Use engineering controls and work practices to

control employee exposure.

■ Establish and implement a written compliance

program to reduce exposures to or below the TWA

and exposure limit.

■ Establish personal air monitoring as well as

information and training programs for employees

exposed to EtO at or above the action level or

above the excursion limit. Conduct training upon

initial job assignment and annually.

■ Establish a regulated area wherever airborne

concentrations of EtO are expected to exceed the

8-hour TWA or the excursion limit.

■ Establish a medical surveillance program for

employees exposed to EtO at concentrations above

the action level of 0.5 ppm, measured as an 8-hour

TWA, for more than 30 days per year.

■ Place warning labels on all containers that might

cause employee exposures at or above the action

level or excursion limit.

■ Remember that employee rotation is prohibited as a

means of compliance with the 8-hour TWA or

exposure limit.

■ Select, provide, and maintain appropriate personal

protective equipment and ensure that employees use

it to prevent skin and eye contact.

When must employers require workers to

use respirators?

Employers must ensure that workers use

respirators to control EtO exposure in the following

circumstances:

■ During installation or implementation of feasible

engineering controls and work practices;

■ During maintenance, repair, and certain operations

when engineering and work practice controls are

not feasible;

■ When engineering and work practice controls are

not currently available to reduce exposures to or

below the PEL; and

■ During emergencies.

What are employers required to do

concerning exposure monitoring?

To help protect workers, employers must conduct

the following exposure monitoring:

■ Initial monitoring to determine the airborne

concentrations of EtO that workers are exposed to

(representative sampling of employees’ exposures is

permitted).

■ Periodic exposure monitoring if the airborne

concentration of EtO is at or above the action level

or above the 15-minute excursion limit.

■ Additional monitoring if there has been a change in

workplace conditions, such as a change in the
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process or materials used, and if the change could

increase employee exposures.

Note: If the exposure level is maintained below the

action level, you may discontinue TWA monitoring until

there is a change in production, equipment, processes,

personnel, or control measures that may result in new

or additional exposure to EtO.

Employers must also do the following:

■ Allow affected employees or their designated

representatives to observe the monitoring.

■ Notify affected employees of the results of the

monitoring within 15 working days of receiving the

results.

Do all businesses where EtO is present need

medical surveillance programs?

Employers must implement a medical surveillance

program, conducted or supervised by a licensed

physician, for an employee under the following

circumstances:

■ If the employee is assigned to an area where

exposure to EtO may be at or above the action level

for 30 days or more during the year.

■ If the employee has been exposed to EtO in an

emergency situation.

What steps must employers take to

communicate with workers about EtO

exposure?

Employers must do the following to communicate

information to affected workers:

■ Establish regulated areas where occupational

exposure to EtO exceeds the 8-hr TWA or

excursion limit, and clearly mark them to limit the

number of workers in the regulated area and to

allow only authorized persons to enter.

■ Provide the signs and labels specified by the

standard clearly indicating EtO’s carcinogenic and

reproductive hazards in regulated areas.

■ Train workers upon initial assignment and then

annually if they are at risk of exposure at or above

the action level or above the excursion limit.

■ Maintain a material safety data sheet for EtO that

conforms to the provisions of OSHA’s hazard

communication standard, 29 CFR 1910.1200(g).

Are there any recordkeeping requirements

concerning employee exposures to EtO?

Employers are required to maintain the following

records relating to employee exposure to EtO:

■ Retain employee exposure records for 30 years.

■ Keep employee medical records for the duration of

employment plus 30 years.

■ Keep records of objective data supporting any

claimed exemption from the requirements of the

OSHA standard.

What should employees do to protect

themselves from EtO exposure?

To protect against EtO exposure, follow these

safety precautions:

■ Wear goggles and skin protection at all times in areas

where there is a risk of splashes from liquid EtO.

■ Wear proper protective clothing and other approved

personal protective equipment when working with EtO.

■ Discard clothing that has been degraded by EtO.

■ See a doctor if you are exposed to EtO.

■ Do not eat, drink, or smoke while working with EtO.

How can you get more information on

safety and health?

OSHA has various publications, standards, technical

assistance, and compliance tools to help you, and

offers extensive assistance through workplace

consultation, voluntary protection programs, grants,

strategic partnerships, state plans, training, and

education. OSHA’s Safety and Health Program

Management Guidelines (Federal Register 54:3904-

3916, January 26, 1989) detail elements critical to

the development of a successful safety and health

management system. This and other information are

available on OSHA’s website.

■ For one free copy of OSHA publications, send a selfaddressed mailing label to OSHA Publications

Office, 200 Constitution Avenue N.W., N-3101,

Washington, DC 20210; or send a request to our

fax at (202) 693-2498, or call us at (202) 693-1888.

■ To order OSHA publications online at www.osha.gov,

go to Publications and follow the instructions for

ordering.

■ To file a complaint by phone, report an emergency,

or get OSHA advice, assistance, or products,

contact your nearest OSHA office under the “U.S.

Department of Labor” listing in your phone book, or

call toll-free at 800) 321-OSHA (6742). The

teletypewriter (TTY) number is (877) 889-5627.

■ To file a complaint online or obtain more information

on OSHA federal and state programs, visit OSHA’s

website.

This is one in a series of informational fact sheets highlighting OSHA programs, policies, or standards. It does

not impose any new compliance requirements. For a comprehensive list of compliance requirements of OSHA

standards or regulations, refer to Title 29 of the Code of Federal Regulations. This information will be made

available to sensory-impaired individuals upon request. The voice phone is (202) 693-1999. See also OSHA’s

website at www.osha.gov.