Recently, we received the following question from a subscriber:
Is there a requirement to have a “CAUTION—MICROWAVE MAY BE IN USE” sign in a warehouse that has a small kitchen with a microwave?
This was our answer:
OSHA does not have specific standards that regulate microwave ovens. The Agency regulates exposure to nonionizing radiation in 29 CFR 1910.97. This standard specifies that worker exposure to nonionizing radiation not exceed 10 mW/cm2 (milliwatt per square centimeter) in the frequency range 10 MHz to 100 GHz (defined in the standard as radio frequency/ microwave radiation).
All microwave ovens produced for sale in the United States must meet the Food and Drug Administration/Center for Devices and Radiological Health performance requirements in 21 CFR 1030.10. This requirement states that new ovens may not leak microwave radiation in excess of 1 mW cm2 at 5 cm from the oven surface. Most manufacturers have standards more stringent than these.
OSHA recognizes that the use of small appliances in offices or break rooms may be comparable to their use in a household and thus would not be expected to present a higher level of hazard. However, a poorly maintained machine potentially could leak radiation.
This OSHA letter of interpretation provides more information on the use of small appliances in the workplace.