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Mercury Management & Exposure Prevention

The Issue:

Mercury has many industrial uses and applications. Upon inspection you will find that it is present in a number of items commonly found in schools. The problem is that most mercury compounds are also toxic and readily absorbed and accumulated by the body. In addition, due to our common use of mercury bearing articles, many individuals have forgotten or assume that elemental mercury and mercury compounds can be highly toxic if mishandled. Some common items often found in schools which contain elemental mercury include: thermometers, barometers, switches, thermostats, flowmeters, lamps, shoes, and laboratory reagents in the science department. Some of the common items found in schools which may contain mercury compounds include: pesticides, paints and stains, laboratory reagents in the science department (e.g. mercuric salts and oxides), batteries, and fluorescent lamps.

Elemental mercury is a volatile toxic heavy metal. Mercury is an unusual metal in that it can evaporate at room temperature. Also, mercury is a neurotoxin which means it can adversely effect the central nervous system. Upon exposure, mercury tends to accumulate quickly in the brain where it tightly binds with the tissue and is released at a very slow rate. In addition, inorganic and organic mercuric compounds are also commonly found in schools. Mercuric compounds can pose the following types of health hazards: toxic to lethal via ingestion or absorption, toxic to the following organs or systems: central nervous system, digestive system, kidney, liver and skin. Many of these materials may also be teratogenic or capable of causing birth defects.

Because mercury and its compounds tend to be readily absorbed and accumulated by the body, it is imperative that we identify potential sources of mercury within the school system as well as potential activities that could result in the release and exposure to these materials. Due to the pervasiveness of mercury and its compounds in the construction of building materials (e.g. thermostats and fluorescent lights) total elimination is not possible. However, the wisest strategy appears to be that of identification and elimination where possible. Where replacement and elimination is not possible, then efforts should be taken to minimize the risk of release of these materials as well as establishing a contingency plan for properly handling any releases that may occur. If proper spill response is not initiated then these materials can pose a long-term health hazard to building occupants. The final component would be establishing policies and procedures for promoting the proper recycling and disposal of mercury and its compounds in order to prevent its release to the environment and to promote compliance with state and federal Universal Waste Disposal requirements..

II. The approach taken:

Our initial step was to review the health hazards associated with elemental mercury and mercuric compounds with the staff. Initially much of the staff was either complacent with regard to considering the hazards posed by these materials or had become "comfortable" due to the historic use of the substances. However, after reviewing available health and safety data as well as anecdotal information, the staff generally agreed that they did not wish to become a "Mad Hatter".

Next, the spill response supplies of each school where mercury and/or its compounds were commonly used were inventoried. As a result, we found that the school department staff had not been trained in spill response procedures and that none of the schools were equipped with a mercury spill kit. Initially, there was no local capability to immediately respond to and mitigate a mercury spill.

Then each school was surveyed for elemental mercury, mercuric compounds, and articles containing mercury. Mercury bearing materials were found in all local schools. The widespread use of mercury in building products guaranteed this observation, but we also noted that experiments and demonstrations involving mercury compounds occurred at all local schools. The prevalence of these materials caused us to review where and how the material was present as well as how it was used. Using this information, we devised a plan to eliminate or replace activities that posed a high risk of release and exposure (e.g. passing electric current through an open container of elemental mercury or activities involving the heating of mercuric compounds). We also attempted to identify mercury bearing items that could not be readily replaced but if broken or improperly managed could create a mercury hazard (e.g. fluorescent lights). Management plans have been created for these items to ensure that these materials are properly recycled/disposed and that accidentally released materials are remediated to eliminate the potential creation of long-term health hazards.

III. Observations made:

The most notable observation made was a general awareness that mercury and its compounds were hazardous to your health. Unfortunately, complacency or familiarity tended to allow much of the staff to overlook these hazards and to continue to use the materials. As a result, several of the common demonstrations and experiments utilized by the staff may have placed the students and faculty at risk to mercury exposure. A benefit of the general awareness was that once reacquainted with the hazards associated with mercury many of the staff were supportive of replacing or removing mercury from the curriculum.

A second observation was that mercury was present in all local schools in a variety of shapes and forms. Elemental mercury and mercuric compounds were used in experiments or demonstrations at all grade levels. In the higher grades, students were occasionally involved with the handling and use of these materials. In addition, mercury bearing materials such as pesticides, paints, and stains were in use throughout the school system. We also noted that some of the students possessed shoes that contained mercury switches which caused their shoes to light up as they walked. As an aside to the case study, many of these shoes have been recalled by the manufacturer due to the potential for these sneakers to release mercury and cause contamination if placed in a washing machine or dryer.

We also noted that the staff had not been advised how to handle a mercury spill and that the school system did not possess spill response materials. As a result, you can only speculate how past releases were handled. Furthermore, we recognized that our capability to respond to a mercury release was severely limited. Therefore, it was possible that a minor mercury spill could create a long-term health hazard if a classroom was not properly decontaminated.

A final observation was that due to the widespread use of mercury in building products, it is not possible to totally remove articles containing mercury from all our local schools. Our approach has been to identify all potential sources of mercury, and to remove/replace what we could and to develop management/disposal practices and spill plans for those items that could not be removed.

IV. Problems or concerns noted:

V. Actions taken:

A. Identified the sources of mercury present in the local schools. Each local school was surveyed in order to identify the type, location, and amount of mercury bearing materials present. This is an ongoing process as we continue to discover additional items that contain mercury. The following is a summary of the items we have identified to date:

containers of elemental mercury laboratory reagents containing mercury
thermometers barometers
flowmeters thermostats
pesticides mercury lamps (indoor & outdoor lamps)
paints & stains fluorescent lamps
mercury switches shoes

B. We identified and eliminated high hazard materials. After identifying the types of mercury present in the local schools, we next reviewed the material with regard to: a) its use, b) its potential for release, and c) the availability of a substitute. Using this criteria, we decided to eliminate the use of mercuric compounds from the curriculum and to drastically reduce the volume of elemental mercury maintained by the school system. As a result, we disposed of 10 pounds of elemental mercury and 3 pounds of various mercuric compounds. Also, steps were taken to discontinue demonstrations involving the unsealed electrification of elemental mercury or the intentional benchtop release of this material. In addition, we also felt that mercury thermometers posed a high risk of release and that these implements could be easily replaced by alcohol thermometers with the same degree of accuracy needed for our uses. This step resulted in the collection and disposal of more than 125 mercury thermometers utilized by the school system. We have also initiated a review of the equipment maintained by the school department in order to identify items containing mercury and to determine their status. During this process we identified a several damaged or obsolete devices containing mercury which have since been disposed.

C. We continue to seek to eliminate other items containing mercury where possible. During our survey, we identified a number of building products which contain mercury such as batteries, paints, stains, thermostats, and fluorescent lights. As these items are consumed or replaced we are endeavoring to locate replacements which are either mercury free or contain less mercury. This is a continuing and evolving process.

D. We have established management/disposal practices for mercury containing articles that remain at the local schools. We recognize that a total elimination of mercury containing articles is not currently possible. As a result, we have developed limited spill response capabilities to address the types of releases that may occur. In addition, we have also established an aggressive plan to identify, manage and recycle all remaining items which contain mercury. Since 1996, we have recycled all dead fluorescent lamps generated by the school system. We are continuing to expand this effort to capture all materials regulated by state and federal Universal Waste Regulations (batteries, computer components, electric ballast's).

VI. Lessons learned:

1. Beware of experiments involving mercury or its compounds. Upon review of the laboratory procedures utilized by the faculty, we found several activities that involved either the electrification of the open containers of elemental mercury, or the intentional release of elemental mercury, or the heating of mercuric compounds. Each of these activities could have resulted in the release of mercury to the classroom and the creation of a long-term exposure risk to the occupants if the material was not properly abated. Due to the inherent volatility of elemental mercury combined with the ability of the body to readily absorb and accumulate mercury along with the difficulty associated with properly cleaning up a mercury release, the wisest approach appears to be to minimize one's exposure to this toxic substance.

2. Identify and inspect all equipment containing mercury. During our review, we found old lamps, a flowmeter, and a damaged barometer containing elemental mercury. The primary concerns associated with the equipment include: a) equipment failure could result in accidental exposure or a release of material, or b) improper disposal of the mercury containing equipment could result in an environmental release of mercury. During our review, we located two mercury lamps that were routinely used by the faculty to provide a comparison of different wavelengths of light. Upon inspection, we noted that the seals on both units were cracked and in poor condition. As a result, it was possible that mercury could slowly evaporate and escape the units over time. The rate of mercury loss may have been accelerated each time the units were turned on and the mercury was heated. The lesson here is know what the equipment contains and what safe guards are required to be maintained in order to safely operate the device.

3. Train and equip your staff for mercury releases. Unless you totally eliminate mercury from your school, you must train and equip your staff for releases. Otherwise you risk creating a long-term hazard in your building. In December 1997, a mercury release occurred at a school in Keene, New Hampshire. The staff recognized that the release posed a health hazard and attempted to respond to the release. Unfortunately, their response was ill conceived. They used a vacuum cleaner to collect the elemental mercury. This approach enhanced the volatilization of the mercury and increased the total area of the school contaminated by mercury. They turned a small manageable problem into a large and costly exposure incident that required professional assistance to resolve. Plan ahead and be prepared.

4. Develop a mercury disposal program. It will be a long time before mercury is eliminated from common building components, so develop a mercury recycling/disposal program to prevent the release of mercury to the environment. This will require you to remove batteries, fluorescent lights and other mercury containing items from your solid waste stream. It is a good thing to do to protect the air you breath and the water you drink and besides it is the law. If these items are disposed of with municipal solid waste then you risk releasing these materials with leachate from local landfills or via the emissions from solid waste incinerators. These requirements are only going to become more stringent over time so be ahead of the learning curve and do it now.

VII. Tips and Suggestions:

1. Learn about what items commonly contain mercury. Our mercury assessment program has been in progress for approximately three years. This is because we continue to discover additional items that contain mercury. I encourage everyone just starting to take the time to try to identify all the items which contain mercury that may be present in their schools.

2. Due to the difficulty in remediating a mercury spill, I recommend that you strongly consider replacing or removing mercury bearing items wherever possible. This approach provides a safer and healthier environment while also reducing your regulatory compliance burden as defined by state and federal Universal Waste Regulations. In addition, improper spill mitigation or waste disposal may also create civil liability for your school and its staff.

3. Recognize that not all mercury can be removed and establish a plan of action for managing the remaining material. You cannot remove everything. So be prepared to clean up a spill involving what is left. Furthermore, establish a procedure to properly dispose of the material when you are finished using it. Most importantly, communicate this information to your staff as a means to ensure that your plans are properly implemented.

4. Review and become familiar with mercury exposure standards. Know and understand what the hazards are. Inform your staff of these hazards. Breaking and releasing the mercury from two sixteen inch thermometers could cause you to exceed the mercury exposure standard established by the federal Occupational Safety and Health Administration if the material is not properly abated. Small quantities can create large problems if not properly handled.

VIII. Resources:

During this investigation, I utilized the resources available via the U.S. Environmental Protection Agency and the Massachusetts Departments of Environmental Protection, Health , Labor and Industries. I also reviewed guidance information prepared by the U.S. Department of Labor Occupational Safety and Health Administration. Due to regional differences with regard to the management and handling of mercury containing waste, I recommend that you consult with your state environmental, health, and occupational hygiene offices, and the regional EPA and OSHA offices prior to establishing your own mercury management plan.

prepared by Todd H. Dresser, Environmental Engineer
(formerly of)
Burlington Board of Health, 29 Center Street, Burlington, MA 01803

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