Mercury and the National Institute of Standards and Technology

Let's first discuss analogies and word meanings by using some examples.

Glycerin is an innocuous water-soluble lubricant. Nitroglycerin is an explosive. Nitroglycerin is prepared from glycerin. It is a different compound.

Mercury is a non-toxic liquid metal. Methylmercury is toxic. Mercury is converted to methylmercury by microorganisms primarily in swamps.

With the recognition that methylmercury is a toxic material, there has been a general panic to eliminate all mercury from the environment. The only justification is that methylmercury is generated by microorganisms in the environment, without human involvement. Contrarily, preparation of nitroglycerin requires a distinct human-controlled operation.

However, the world is not one big swamp with mercury converting microorganisms ready to do their damage. Laboratories, where mercury has been used in thermometers, do not contain these microorganisms. Similarly, houses using mercury containing thermostats do not contain these microorganisms. The only source of mercury susceptible to conversion to methylmercury is that from coal-fired power plants. Emissions from such power plants contain small amounts of mercury which pervade the atmosphere and fall into swamps where the microbiological conversion to methylmercury takes place. Controls on coal-fired power plants continue to be instituted to reduce the source, even though the generated quantities of methylmercury are very small and dissipate into the general atmosphere.

Mercury containing thermometers used in laboratories is encapsulated within the glass bulbs of thermometers. If the bulbs break, the mercury is spilled. In the general interest of laboratory cleanliness and economy, spilled mercury is routinely physically recovered. Very small droplets are made to react with sulfur to form a solid material, which can be swept up, or with zinc to form a solid amalgam, which can similarly be easily collected. Many mercury compounds are not toxic to humans. In fact, mercuric oxide has been used for many years to treat eye infections.

With that background of technology and logic, we can proceed to the main point of this message.

The National Bureau of Standards was established by Congress in 1901. The purpose was to establish standards of measurement for uniformity in science and industry. For example, what is the standard length of a meter? What is the standard weight of a pound? The Bureau did its job well and we have no confusion in measurement standards.

However, subsequent political motivations have changed the nature of the Bureau, including its name, which is now the National Institute of Standards and Technology. The name change is associated with a change in policy. For example, part of the Institute's new responsibilities is to promote US industry. Presumably the justification for this is that the NIST is a part of the Commerce Department. The difficulty arises in that adding the new responsibility also leaves the Bureau open for other political maneuvering.
In its new political role, NIST has assumed the responsibility of removing mercury containing thermometers from society. As shown above, there is no technological justification for such action, nor does NIST have the right to assume that responsibility. This is another of many cases of government "overreach".


The argument can be presented that technology changes in temperature measurement have outmoded the need for mercury thermometers. It is a fact that digital thermometers have become the workhorse of temperature measurement in laboratories, industry and the home. It is also a fact that temperature can be measured by resistance changes in platinum. It may be that the NIST is now using this technology as a standard for temperature measurement. If so, I have no objection to this switch based upon the improved technology.

With the increased use of digital thermometers, the requirement of calibrating a mercury thermometer has become unnecessary. The Bureau previously ran such calibrations for industry on a fee basis and that requirement has dropped off such that the bureau is justified in no longer offering thermometer calibration service. However, a requirement for calibration of digital thermometers now is necessary, and I am wondering what the bureau is doing about that. If it does not offer such service, I also have no disagreement. Maintaining a temperature measurement standard and offering a calibration service are two different things. I hope that the Bureau maintains the temperature measurement standard, so that all in science and industry can be equally confident of the equality of heat involved in a standard degree Fahrenheit or Centigrade.

When people get involved in political considerations, they tend to lose sight of scientific facts. I would like the NIST to act like a Bureau of Standards, rather than a political body such as the EPA.