Mercury Information

by Dan Napier, MS


Mercury is a naturally occurring element that is found in air, water and soil. It can be elemental or metallic mercury, inorganic mercury compounds, and organic mercury compounds.


Elemental or metallic mercury is a shiny, silver-white metal and is liquid at room temperature. It is used in thermometers, fluorescent light bulbs and some electrical switches. When dropped, elemental mercury breaks into smaller droplets which can go through small cracks or become strongly attached to certain materials. At room temperature, exposed elemental mercury can evaporate to become an invisible, odorless toxic vapor. People can be exposed to elemental mercury vapor when products that contain mercury break and expose mercury to the air, particularly in poorly-ventilated spaces. People have boiled mercury inside homes, the result is that the house had to be demolished.

Inorganic mercury compounds take the form of mercury salts and are generally white powder or crystals, with the exception of mercuric sulfide (cinnabar) which is red. Inorganic mercury compounds have been included in products such as fungicides, antiseptics or disinfectants. Some skin lightening and freckle creams, as well as some traditional medicines, can contain mercury compounds. Mercury was used in paints to help prevent mold.

Organic mercury compounds, such as methylmercury, are formed when mercury combines with carbon. Microscopic organisms convert inorganic mercury into methylmercury, which is the most common organic mercury compound found in the environment. Methylmercury accumulates up the food chain. Tuna is a fish that eats other fish and that is why tuna can have higher levels of Mercury than a fish that does not eat other fish.


The Food and Drug Administration (FDA) maintains a list of medicines that contain mercury.

Mercury is very costly to dispose. The best recommendation is that mercury be recycled. Mercury can be in an almalgum and as such it is locked up and not hazardous. Mercury can contaminate soft materials and persist for a very long time. Most mercury problems are made worse when inexperienced well meaning people get involved.

EPA has a list of things that should not be done.

Never use a vacuum cleaner to clean up mercury. The vacuum will put mercury into the air and increase exposure. The vacuum appliance will be contaminated and have to be thrown away.

Never use a broom to clean up mercury. It will break the mercury into smaller droplets and spread them.

Never pour mercury down a drain. It may lodge in the plumbing and cause future problems during plumbing repairs. If discharged, it can cause pollution of the septic tank or sewage treatment plant.

Never wash mercury-contaminated items in a washing machine. Mercury may contaminate the machine and/or pollute sewage.

Never walk around if your shoes might be contaminated with mercury. Contaminated clothing can also spread mercury around.

A spill of mercury should be cleaned up carefully, the EPA web site has very good and specific instructions. Read the information and follow the guidelines carefully.


If you have any questions or need help contact a Certified Industrial Hygienist (CIH). They a qualified to provide the best information to assist you. To see the qualifications go to the ABIH web site for more information, and to find a CIH near you.

Mercury testing equipment is very sensitive, and costly to maintain. We own the most sensitive mercury testing equipment available. Please do not hesitate to call me for assistance or other questions.

Dan Napier, MS, CIH, CSP 800-644-1924