Safety risks are associated with even normal microwave use. Steam can build if food is microwaved in airtight containers, causing a risk of severe burns or injuries. Glass containers may also shatter due to internal pressure as steam builds. For this reason don't microwave baby bottles. Also provide ventilation to microwaved food containers by leaving a corner of the container uncovered or by fitting covers loosely over the containers.
Microwave ovens are dangerous to repair because of high voltage. Repair technicians should always wear rubber shoes or sneakers to mitigate the risk of electrocution and should perform repairs with the unit unplugged. Always leave repairs to qualified service personnel to lower the risk of electric shock or electrocution.
Cover Replaced Incorrectly
The screws holding the cover of the microwave on are not alike; if a repair technician removes the cover, he must put the screws back in the proper place. As a safety feature, some microwaves will not power up if a screw is missing or in the wrong place. In addition removing the cover usually voids any warranty on the microwave, so if you take the microwave to a service center because the cover was not put back on properly, it may cost a bit.