Microwave Leakage

Honest Home Inspections will gladly test for Microwave Leakage in your home, see the "Fees and Services" page for details. Microwave Leakage detection is included in any inspection where the microwave is part of the sale of the property. The following information will try to answer questions you have in regards to Microwave radiation. 

Have you ever watched up close as your leftovers heated in a microwave oven? Has your child? How much body penetrating microwave radiation do you think you took in? Would you like to know before you do it again?

Microwave oven leakage is serious business. Every year millions of children, pregnant women, and people of all ages stand too close to an operating microwave oven, exposing themselves to dangerous levels of body penetrating microwave radiation. Microwave radiation is known to cause cataracts, birth defects, cancer and other serious health problems. Warning labels are included in every oven owner's manual. The FDA takes the problem so seriously, it has set legal limits on the amount of leakage permitted.

Does your Microwave leak?

So you are about to buy your dream home with that great kitchen and a built in microwave above the stove. How convenient. But how old is that microwave and what kind of shape is it in? Microwaves have been around for decades. The real push began after 1975 and now 90% of US homes have a microwave oven. Therefore that microwave that looks fairly new could in fact be quite old. But age doesn't really matter too much. Leakage does!

What is Microwave Leakage?

Microwave leakage is a big enough concern that the FDA has established limits as to microwave leakage. There is little cause for concern about excess microwaves leaking from ovens unless the door hinges, latch, or seals are damaged, or if the oven was made before 1971. All microwave ovens made after October 1971 are covered by a radiation safety standard enforced by the FDA. The standard limits the amount of microwaves that can leak from an oven throughout its lifetime. The limit is 5 milliwatts of microwave radiation per square centimeter at approximately 2 inches from the oven surface. This is far below the level known to harm people. Furthermore, as you move away from an oven, the level of any leaking microwave radiation that might be reaching you decreases dramatically. For example, someone standing 20 inches from an oven would receive approximately one one-hundredth of the amount of microwaves received at 2 inches.

How does leakage occur?

Leakage will normally occur through the microwave door. Microwave leakage is a big enough concern that, as mentioned before, the FDA has established limits as to microwave leakage. Be wary of any that appear to have a damaged door, seal or hinges. Since the door is really where leakage occurs most of the time it is dependent on the use and care the microwave has seen over the years. Many of the microwaves permanently mounted above the stove are absorbing a great deal of heat and contaminants from the stove itself. The door seal is our concern and many times all it takes is just a good cleaning (see Tips on Safe Operation below). Others need to have the seal replaced or at times it may be worth replacing the unit.

How is the radiation measured outside the microwave?

Microwave radiation is measured as power density in units of milliwatts per square centimetre (mW/cm²) which is essentially the rate of energy flow per unit area. One needs special equipment for the detection and measurement of the leakage. Typical levels of radiation leakage from microwave ovens is about 0.2 mW/cm² which is far below the limit set by the national safety standard Safety Code 6: Limits of Exposure to Radiofrequency Fields at Frequencies from 10 kHz-300 Ghz (1994, 60 p., Health Canada pub. 91-EHD-160) and the FDA. This level of leakage cannot be sensed by the body.

How does Honest Home Inspections test the Microwave for leakage?

We are using a digital microwave oven leakage detector. Measurements shall be made with the microwave oven operating at its maximum output and containing a load of 275±15 milliliters (1 cup) of tap water initially at 20°±5° Celsius 68°±5° Fahrenheit placed within the cavity at the center of the load-carrying surface provided by the manufacturer. The water container shall be a low form 600-milliliter beaker having an inside diameter of approximately 8.5 centimeters (3.34 inches) and made of an electrically nonconductive material such as glass or plastic. Measurements shall be made with the door fully closed as well as with the door fixed in any other position, which allows the oven to operate. The meter will be placed approximately 2" from the microwave door seal and measured across the entire seal length. Our meter is capable of a range from 0 - 9.9 mW/cm² (no more than 5 MW is recommended by the FDA).

Tips on Safe Microwave Oven Operation

  • Follow the manufacturer's instruction manual
    for recommended operating procedures and safety precautions for your oven model.
  • Don't operate an oven if the door does not close firmly or is bent, warped, or otherwise damaged.
  • Never operate an oven if you have reason to believe it will continue to operate with the door open.
  • Some ovens should not be operated when empty. Refer to the instruction manual for your oven.
  • Clean the oven cavity, the outer edge of the cavity, and the door with water and a mild detergent. A special microwave oven cleaner is not necessary. Do not use scouring pads, steel wool, or other abrasives.
  • To add to the margin of safety already built into the oven, don't stand directly against an oven or peer inside of the oven (and don't allow children to do this) while it is operating.
  • Users should not heat water or liquids in the microwave oven for excessive amounts of time a phenomenon of superheating can occur. Visit www.fda.gov/cdrh/consumer/microwave.html#11 for information on superheating.