Removing Mercury from Hospital Labs

Mercury is prevalent in the hospital laboratory and may be difficult to find. Here are some problems you may face:

Steps for Tackling Mercury in the Lab

Step 1. Examine Chemicals and Reagents
Examine the container labels, MSDSs, and reagent inserts. Look for the presence of mercury. Remember that mercury may be present at troublesome levels, even if it is not listed on the MSDS, label or insert! Manufacturers are not required to list hazardous components of a product unless that component is present at a level of > 1% (0.1% for carcinogens). A product can contain up to 10,000 ppm before a manufacturer is required to list mercury as a component. Don't forget to examine cleaning agents, soap, scouring pads, and other laboratory supplies. Eliminate the use of any home cleaning products used in the lab. Home cleaning products may contain high levels of mercury and even if the mercury was flagged on an MSDS, OSHA does not require MSDSs be provided for household consumer products when the products are used in the workplace in the same manner that a consumer would use them.

Step 2. Require Vendors and Manufacturers to Disclose all Hazardous Materials in Their Reagents

When setting up contracts to purchase equipment and reagents, make disclosure of all hazardous materials in the reagents a required part of the contract. Remember that an MSDS is not sufficient unless the company has a policy of disclosing all hazardous materials on their MSDSs (and they need to sign off to the lab that they do that).

Step 3. Eliminate Instrument and Equipment Contamination

Any equipment known to have been used with mercury reagents or thermometers should be tested for mercury contamination (water baths, instrument tubing and containers, electrophoresis cells, etc.). Run rinse solutions through instruments and rinse any equipment. Collect the rinse solution, carefully label, and send out for mercury testing. Be careful not to contaminate new equipment by exposing it to mercury!

Step 4. Keep Working Even After Eliminating All Known Mercury Sources

In some cases, analysis of the laboratory waste stream continues to show mercury even after all known sources of mercury are eliminated. Here are some steps to consider:

Table 1. Synonyms and Trade Names for Thimerosal
Compiled by Melissa McCullough, Dana Farber Cancer Institute

Ethyl (2-mercaptobenzoato-S) mercury sodium salt
[(o-carboxyphenyl)thio] Ethylmercury sodium salt
o-(Ethylmercurithio)benzoic acid sodium salt
Elcide 75
Ethylmercurithiosalicyclic acid, sodium salt
Ethylmercurithiosalicylate sodium
Ethylmercurithiosalicylate sodium salt
Mercurate(1-), {ethyl[o-mercaptobenzoato(2-)]-,} sodium
Mercurate(1-), {ethyl[2-mercaptobenzoato(2-)-O,S]-,} sodium
Mercury, ethyl(hydrogen o-mercaptobenzoato)-, sodium salt
Mercury, ethyl(2-mercaptobenzoato-S)- sodium salt
Mercury {[(ocarboxyphenyl)thio]ethyl}-sodium salt
Merseptyl (VAN)
Merthiolate salt
Merthiolate sodium
Merzonin sodium
Merzonin, sodium salt
Sodium ethylmercurithiosalicylate
Sodium ethylmercuric thiosalicylate
Sodium ethylmercurithiosalicylate
Sodium merthiolate
Sodium o-(ethylmercurithio)benzoate
Sodium salt of 2-(carboxyphenyl)thioethylmercury
Sodium 2-(ethylmercurithio)benzoate
Thimerosal solution
Thimerosol solution

The SHP thanks the following people for their significant contributions to this fact sheet:
Melissa McCullough, Dana Farber Cancer Institute
David Wintz, Indiana Department of Environmental Management
Catherine Zimmer, Minnesota Technical Assistance Program


For information on mercury alternatives, visit the Sustainable Hospitals Project website at or contact us at or 978-934-3386. - Click on "MWRA/MASCO Mercury Workgroup"
This website includes resources to prevent discharge of mercury in wastewater, including a Mercury Management Guidebook, based on the successful efforts of Boston area hospitals to meet the 1 part per billion mercury discharge limit set by the local wastewater treatment plant.
This website provides tools, including purchasing language, for minimizing the volumes of waste generated and the use of persistent, bioaccumulative, and toxic chemicals. In the Mercury section of the website, check out the "Mercury Virtual Elimination Plan"