Dental Program

Silver tooth fillings


Dental amalgam, the material in “silver” tooth fillings, contains approximately 50% mercury. Used as a dental restorative material for over 150 years, amalgam remains popular because it is strong, durable and relatively inexpensive. Roughly 200 million restorative procedures performed in 1990 used amalgam. Amalgam use is declining because the incidence of caries is decreasing and because improved substitute materials are now available for certain applications.

Dental amalgam is a known source of mercury to the environment. The Western Lake Superior Sanitary District (WLSSD) determined that 10-15% of the mercury it received in wastewater was from the dental community. Mercury is a potent neurotoxin that is especially harmful to developing fetuses and can cause sensory loss, tremors, loss of muscular coordination, speech, hearing, and visual problems, as well as increased risk of heart attack. See more

During installation and removal of mercury fillings, small bits of amalgam can be released to the waste stream. Mercury cannot economically be removed at the treatment plant, so making sure it does not reach the waste stream (sewers) and ultimately the environment is imperative.

Program Details


As of 2016, all dental facilities that handles amalgam must be be part of the Pretreatment Program. Dental facilities must follow best management practices for amalgam handling, operate an amalgam separator, and recycle collected amalgam. Following these practices prevent the discharge of mercury into City sewers and ultimately in our environment.

Previously, the City of Superior developed dental trainings based, in part, on the work of Tim Tuominen, Chemist at the WLSSD.
Between the Fall of 2002 and May 2003, City personnel visited 14 Douglas County dental offices and provided training in amalgam recycling through chair side traps and amalgam separators and BMPs for dental hazardous wastes. The training, which was endorsed by both the Minnesota and Wisconsin Dental Association, took place on-site at a time convenient to the doctor and his/her staff. Participating dental office workers could earn a Continuing Education Credit by completing and passing a test developed by the Minnesota Dental Association (MDA). In addition, each dentist participating in the training had the opportunity to win a free amalgam separator from Rebec Simple Solutions.

Drs Callaway receiving amalgam separator
Above: Dr. Mark Callaway and Dr. Allen Callaway, winners of the free CatchHG Separator (May 30, 2003). The CatchHG is known as the standard by which all other mercury recovery devices are judged for ease of operation, affordability and environmental safety.