M-Press Systems (M) Sdn. Bhd.
Industrial Microwave-, Plasma-, RF- and Control-Systems

Microwave &Amp; Health

In recent years people are getting more and more aware about possible health risks originating from the daily use of equipment like home appliances, hand phones etc., or the exposure to electromagnetic fields from high tension power lines and other sources. In the following we want to give you a short overview about possible risks originating from the use of industrial microwave equipment, and what you can do to keep these risks to a minimum.

Nature of microwave radiation

As also mentioned on our webpage microwave basics, microwave radiation is a non-ionising type of electromagnetic radiation, the photons of microwave radiation are actually carrying less energy than the photons of visible light. Therefore there are no health risks like, for example, genetic damage, which are usually associated with ionising radiation like X-rays, gamma rays, radiation from radioactive materials etc. Neither is there a risk that food or other products exposed to microwave radiation start to "radiate" by themselves. In order to evaluate the other risks posed by microwave radiation we have to look at two different scenarios, one being the exposure to low levels of microwave energy and the other one being the exposure to high levels of microwave energy. Other possible risks for health (or even life) when working with industrial microwave systems or parts thereof are listed further down.

Risks from low level microwave energy

Low levels of microwave radiation are typically emitted by hand phones, IT equipment like wireless routers, household microwave ovens etc. As for industrial microwave systems, there are laws and regulations how much energy can be emitted by this equipment, and these levels are deemed to be safe and to pose no risk to human health. While many people are worried that microwave radiation will cause the molecules inside our bodies to move rapidly and eventually "break", it is important to understand that these molecules are in a permanent motion anyway, due to the fact that our body temperature is above absolute zero. Countless studies could so far not prove any negative effect of low level microwave radiation on the human body, even though there is no 100 % certainty that, under extreme circumstances, there might be a negative effect.

Risks from high level microwave energy

Humans are in general only exposed to high levels of microwave radiation if equipment has been tampered with, it is used carelessly or against the operation instructions, or when people enter areas where high levels of microwave energy cannot be avoided, e.g. in the surrounding areas of high-power radar installations. Due to the effect of dielectric heating, body parts exposed to high energy levels can get heated up rapidly, which can lead to severe burns or even death. However, the most sensitive parts of the human body are the lenses of the eyes, because they do not contain any blood vessels and can therefore only be cooled via thermal conduction and radiation. If the eyes are exposed to even moderate levels of microwave energy, the lenses will overheat and the proteins inside will denature, making them opaque, which is also known as a cataract and can lead to total blindness. It is therefore of utmost importance not to tamper with any parts of the equipment, or to start up generators which are not connected to a proper load. Doors, in- and outlets, waveguide connections etc. should be checked on a regular basis to detect any abnormal increase in leakage radiation and to avoid any negative effects on human health. We offer portable as well as fixed / stationary leakage detectors for this purpose, which will help to reduce any possible risk to a minimum.

Risks from electrical shock

All Magnetrons require a high voltage DC power supply for their operation, depending on the model and output power this voltage ranges from around 2 kV (2000 V) to 15 kV and above. Because these power supplies can deliver up to several amperes of output current, any contact with the DC supply is absolutely lethal, even removing the cover from a household microwave can already be deadly. Microwave systems must therefore only be serviced by people who are aware of the dangers and know how to handle them.

Risks from magnetic fields

Another prerequisite for the operation of a Magnetron is a strong magnetic field, which is generated by the permanent magnets build inside the Magnetron. Under certain circumstances this magnetic field can interact with nearby electronic equipment and cause it to malfunction, for this reason people with pacemakers should not handle or get to near to Magnetrons.

Risks from toxic substances

Certain types of medium to high power Magnetrons are using a special type of ceramics for the insulation of the antenna, known as Beryllium oxide or Beryllia, due to its outstanding mechanical and electrical properties. While safe in normal handling, Beryllia becomes dangerous once it occurs in the form of dust. If inhaled, this dust can lead to beryllium disease, an incurable chronic lung disease, and even cancer. While in many countries, e.g. the USA, Beryllia ceramics itself is not classified as a hazardous waste, under no circumstances Magnetrons should be dismantled or otherwise damaged, even after use. If a Magnetron is accidentally dropped and the antenna breaks as a result, wear proper safety gear (gloves, goggles, respirator) and make sure you collect all debris including small particles, e.g. by the use of a vacuum cleaner with a suitable filter system, and dispose them a hazardous waste.