Is it permissible to use a residential microwave in the lab to heat up samples of ceramic substrate?

Microwaves approved for preparing food — at home or at work — would be fine at work for the intended purpose but one being used for other purposes may present a problem for OSHA unless it is approved for both applications. In a letter of interpretation 08/08/2002 – Applicable OSHA standards and safety considerations for microwave device use in a lab, OSHA states:

“If a household microwave oven was accepted, certified, listed, labeled in accordance with UL 923, Microwave Cooking Appliances, and it was placed into use in a laboratory ... this would not meet the OSHA requirement in 29 CFR 1910.303(b)(2) that the equipment be used in accordance with any instructions included in the listing or labeling. The safety instructions in UL 923 state, ’Use this appliance only for its intended use as described in the manual. Do not use corrosive chemicals or vapors in this appliance. This type of oven is specifically designed to heat, cook, or dry food. It is not designed for industrial or laboratory use.’ However, if a household microwave oven is accepted, certified, listed, labeled, or otherwise determined to be safe by a nationally recognized testing laboratory (NRTL) for a standard that includes laboratory use, then OSHA would consider it acceptable.”