In early 2017, a NJ Education Association Work Environment Council flier reported that phenyl mercuric acetate (PMA) may have been used in as a curing agent in synthetic rubberized flooring. The New Jersey Department of Health (NJDOH) also issued a fact sheet in early 2018. From the 1960s to the early 2000’s, schools, communities, colleges, universities, prisons throughout the country installed indoor gymnasiums, field houses, outdoor running tracks and similar rooms and athletic facilities. According to the 3M Corporation, their Tartan® brand polyurethane flooring product (along with 8 other known brands) may contain as much as 1,000 – 2,000 parts per million (mg/kg) total mercury. It is now known that the PMA breaks down to metallic mercury over time, which is released as a vapor into the air. Based on the available literature and our own experience, metallic mercury vapors and mercurycontaining dust have been reported at elevated levels as a result.
While this emergent issue has been evaluated by a handful of other states, there are no statutes, regulations, or detailed guidance to address the potential impacts from mercury in flooring. The federal Agency for Toxic Substances and Disease Registry (ATSDR) and state health departments appear to be the lead agencies involved in evaluating the issue. While not required, it is recommended that the NJDOH should be utilized as a resource and provided with a copy of the results. The New Jersey Department of Environmental Protection (NJDEP) does not regulate building materials, but would regulate the disposal of the impacted flooring.
Exposure to mercury can primarily affect 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. The initial neurological effects may result in hand tremors, an increase in memory disturbance, and evidence of autonomic dysfunction. Mercury exposure is not known to cause cancer or autism.
In order to evaluate suspect facilities, it is recommended that bulk sampling of the rubberized play surfaces be conducted by a NJDOH Licensed Indoor Environmental Consultant to determine the potential presence of total mercury above 1 mg/kg. This can be done in unobtrusive locations in many instances, i.e., under roll out bleachers. 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. Above this level, conducting further indoor air sampling and remedial action is warranted.
Where floor bulk-sampling results exceed 1 mg/kg total mercury, or destructive sampling is not feasible, an indoor air investigation using a mercury specific analyzer is recommended to assess the potential for metallic mercury vapor to be present. The ATSDR recommends that if metallic mercury vapor in the air is greater than 0.8 part per billion (µg/m3), which is consistent with NJDEP’s 1 µg/m3 indoor air screening level, additional remedial action is needed.
The evaluation of mercury migration as vapor and dust throughout the facility should also be considered. Mercury floor remediation projects often only focus on the flooring itself. Due to the potential for impacts mercury containing dust to heating/air conditioning/ventilation systems, architectural features, and exterior areas, a concurrent evaluation of mercury containing dust is recommended.
Depending on site-specific conditions, complete floor removal and disposal should be considered as a permanent solution. Removal of the mercury impacted should be considered based on the air concentrations along with the age and condition of the flooring. Prior to removal and disposal of any impacted floor material, sampling and analysis the flooring according to United States Environmental Protection Agency and NJDEP hazardous waste regulations is recommended. 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 to solicit bids from qualified contractors.
An alternative to removal is the short-term encapsulation of the floor coupled with controlling the air temperature in the affected areas. Diligent year round temperature control to 65 – 68° F is recommended to minimize the volatilization of mercury vapors and routine air sampling should be conducted to affirm safe air levels. Note that increased energy costs in the summer months may, however, off-set the short term savings over time. This strategy does not address potential dust impacts, but could be effective before implementing a long term removal remedy.
Case Study (Urban Public School District)
PennJersey assisted one of the largest urban districts in NJ by evaluating seven facilities with rubberized flooring in June 2017. Each facility was evaluated by collecting bulk samples of the flooring and by sampling the indoor air samples with the mercury specific analyzer. Of the seven facilities evaluated, three were identified with elevated levels of mercury in the rubberized flooring and in the indoor air. PennJersey developed a comprehensive specification for the removal of mercury impacted rubber flooring and cleaning for these three facilities, and public bidding for floor removal and replacement was conducted. In this case, the flooring was not removed, but was covered with a barrier, new flooring, and the interior temperatures maintained at 65° F to minimize the generation of mercury vapors. Post remediation results were reported to have been acceptable, however, increased energy costs have been identified as an ongoing issue.
- ATSDR, Action Levels for Elemental Mercury Spills, March 22, 2012.
- NJ Education Association Work Environment Council, HSN Alert: Mercury Hazard to Staff and Students from Rubber-Like Floors in Schools, February 2017.
- Ohio Department of Health and ATSDR, Mercury in Flooring Presentation, presented at the Building Environment Council of Ohio Fall Conference October 21, 2010.
- USEPA, Integrated Risk Information System: Elemental Mercury, June 1, 1995.
- NJDOH, Guidance for New Jersey Schools: Evaluating Mercury in Synthetic Flooring,
PennJersey is a small, specialized environmental consulting firm located in Milford, New Jersey. We manage the environmental needs of a variety of clients in the public and private sectors. Our primary focus is on assisting our clients through the site assessment and remediation processes. Throughout our engagements, PennJersey acts as an advocate for our clients while satisfying the myriad of regulatory and technical issues that can arise to complicate a project. PennJersey is licensed by the NJDOH as an Indoor Environmental Consultant (#1219).
For More Information, Contact
Rodger Ferguson, LSRP William Call, PG LSRP Brad Musser, LSRP
(908) 329-6060 x8450 (908) 329-6060 x8453 (908) 329-6060 x8454