Recently, a NJ Education Association (NJEA) / Work Environment Council (WEC) flier reported that phenyl mercuric acetate (PMA) may have been used in synthetic rubber-like flooring. From the 1960s to the mid-1990s, schools, colleges/universities, athletic facilities, prisons and other facilities throughout the country installed indoor gymnasiums, field houses, outdoor running tracks and similar rooms and facilities. When mixing the polyurethane formulation to form the rubberized floor surface, PMA, was used t
o facilitate the liquid’s spreading and leveling. According to the 3M Corporation, their Tartan® brand flooring product (along with 8 other brands) may contain 0.1% to 0.2% mercury (1,000-2,000 mg/kg). Based on the available literature and our own experience, metallic mercury vapors have been reported at elevated levels in these facilities.
While this emergent issue has been evaluated by a handful of other states, the State of New Jersey and the United States Environmental Protection Agency (USEPA) have no formal regulations or guidance promulgated to address the potential for mercury in flooring. The federal Agency for Toxic Substances and Agency for Toxic Substances (ATSDR), working with state health departments, appears to be the lead agencies involved in evaluating the issue. The New Jersey Department of Health (NJDOH) is aware of the issue and may be issuing guidance shortly.
Exposure to mercury can primarily effects the neurological system, including the brain, as well as the kidneys or a developing fetus. Children and pregnant women are at greatest risk from mercury exposure, but occupational exposure is well known. We all remember the Mad Hatter from Alice in Wonderland. The initial neurological effects may result in hand tremors, an increase in memory disturbance, and evidence of autonomic dysfunction. Mercury is not known to cause cancer.
In order to evaluate suspect facilities, it is recommended that bulk sampling of the rubberized play surfaces be conducted to determine the potential presence of PMA at actionable levels (i.e., above 1 mg/kg). If actionable mercury concentrations are identified in the bulk sampling, further remedial actions or conducting further indoor air sampling is warranted. If total mercury is less than 1 mg/kg, it can be assumed that the flooring was not manufactured using a mercury-containing compound such as PMA.
Where floor bulk-sampling results are in excess of 1 mg/kg total mercury, performance of an indoor air (IA) investigation is recommended to assess the potential for mercury to be present as a vapor hazard in these areas. The ATSDR recommends that if a floor emits mercury vapor greater than 0.8 µg/m3, or if laboratory analysis detects mercury at a concentration of 20 mg/kg or greater, the best permanent solution is to remove the floor and replace it with a floor that does not contain mercury. The ATSDR recommends a 3 µg/m3 clearance concentration for the air in schools. NJDOH regulations allow for calculation of a site-specific action level. The evaluation of mercury migration throughout the facility should also be considered. While not required, the state health department should be utilized as a resource and provided with a copy of the results.
Additionally, sampling of the surface(s) and materials below the rubberized flooring is recommended to determine if there have been sub-flooring impacts by the mercury. This is typically accomplished by advancing core samples through the floor of each affected area and sampling of the top layer of concrete sub-flooring under the rubberized surfaces to evaluate the potential for vertical downward migration of mercury.
Depending on site-specific conditions, disposal should be considered, but active ventilation could also be a short-term option. Prior to removal and disposal of any impacted floor material, sampling and analysis for USEPA Resource Conservation and Recovery Act waste characteristics including the Toxicity Characteristics Leaching Procedure methodology is recommended, and a comprehensive removal specification, which includes comprehensive air monitoring for the protection of the workers and building inhabitants during the replacement of the flooring, is recommended.
ATSDR, Action Levels for Elemental Mercury Spills, March 22, 2012.
NJEA/WEC, HSN Alert: Mercury Hazard to Staff and Students from Rubber-Like Floors in Schools, February 2017.
ODOH/ATSDR, Mercury in Flooring Presentation, presented at the Building Environment Council of Ohio (BECO) Fall Conference October 21, 2010.
USEPA, Integrated Risk Information System (IRIS): Elemental Mercury, June 1, 1995.
William P. Call, P.G., LSRP
Mr. Call holds a geology degree from Rensselaer Polytechnic Institute and has provided environmental services since 1987. Mr. Call is a Professional Geologist (PA & AR) as well as a Licensed Site Remediation Professional and serves on the Board of Trustees of the Licensed Site Remediation Professional Association, where he also serves on the Risk Management and Loss Prevention Committee and co-chairs the Continuing Education Committee. Mr. Call has developed and implemented numerous projects involving investigations of various hazardous waste facilities and related site remediation projects. These projects have included State, County, municipal and commercial properties impacted by various operations. Past project experience includes various environmental investigations; remediation of major New Jersey educational, road expansion, and Brownfields projects; sites impaired by leaking underground storage tanks; Industrial Site Remediation Act investigations; Resource Conservation and Recovery Act site closures; and extensive hydrogeological investigations. When he is not cleaning up New Jersey one site at a time, he dedicates his free time to taking care of his young daughter, a new home and getting in some crossbow archery. As a new homeowner in town, Mr. Call is also joining the Middletown Township Environmental Commission.
• NJ Licensed Site Remediation Professional 573657
• NJ UST Subsurface Evaluator 0010212
• NJ Soil Borer 0023686
• PA Professional Geologist PG003036G
• AR Professional Geologist 1672