Mercury within Rubber-Like Floors in Schools

  • 2019-06-20

Establishing a Review and Action Plan

 By D. Joshua Cupriks, CIH Northeast Regional Safety Manager, Gallagher Bassett


Polyurethane floors with phenyl mercuric acetate (PMA) catalyst were commonly installed in many school multipurpose rooms, gyms, cafeterias, auditoriums, stages, and indoor and outdoor tracks from the 1960s onward. PMA breaks down over time and increases the potential for release of odorless, colorless mercury vapor at room temperatures into surrounding area(s). The floors and construction/finishing items in contact with them may indefinitely emit mercury vapor under certain conditions. This is a nation-wide issue affecting an unknown number of schools and similar spaces. Identification and removal of mercury-containing floors in Gloucester County, New Jersey (among other) public schools have recently been in the news.

Not all flooring that contains mercury emit mercury vapors into the air, but generally, mercury vapor exposures are worse if floors are damaged or deteriorated, in warm/hot rooms with little to no dilution (i.e., outside air) ventilation, or without air conditioning. Exposures are typically greater at or near floor level where children spend extended period of time during use.

Likely routes of exposure include inhalation of mercury vapor and skin contact/absorption. In the right dose, mercury can be hazardous to the central nervous system, kidneys, lungs, eyes and skin. Therefore, children and pregnant (or soon to be pregnant) individuals present the greatest risk with additional exposure concerns for staff and older students. Risk always varies with the level of mercury exposure among other health factors (i.e., concentration, duration, age and health status).

A number of professional organizations recommend similar elements of an Action Plan:

1) Build group consensus (i.e., school staff, parents and communities) with the help from a Health & Safety committee.

2) Obtain the services of a Certified Industrial Hygienist (CIH) to help guide your Team through the process.

3) Professionally and representatively assess/test suspect flooring.

4) Floors with leachate that exceeds the US EPA maximum concentration of 0.2 ppm (mg/L) of mercury must be disposed of as hazardous waste. If mercury in floor levels are greater than one (1) ppm, proper floor maintenance, adequate ventilation and cooling and initial/worst-case air sampling should be implemented.

5) Develop procedures (i.e., ventilation, gym use/maintenance, surface hygiene, etc.) needed to control exposures while floor/space is in use as referenced at the end of this bulletin.

6) Coordinate decisions with all Team members regarding public awareness/training/path forward decisions (i.e., including but not limited to community groups, staff, labor unions, affected families, attorneys, insurance carriers and health professionals.

7) Develop plans for maintenance, mitigation (i.e., removal/replacement or sealing) with cost analysis/budgeting for indefinite support services versus floor replacement. Maintaining such a floor in place may be expensive, so be sure to include all professional and mechanical costs.

A number of airborne mercury criteria are available for review depending on your State Department of Health and your Team’s level of determined acceptable risk/concern. Well-regarded guidance includes but is not limited to the following:

General Consensus: There are no regulations currently requiring removal of an installed mercury-containing floor. Mercury floors may be managed in place under the right conditions. Necessary components include:

1) Initial professional assessment. In some cases, floors may be old (40+ years) and in need of replacement regardless.

2) Functional and effective HVAC system/ventilation dilution ventilation (i.e., outside air changes) in order to offset vapor release levels. The supplemental services of an industrial ventilation engineer to make additional system changes as required by the project CIH/Project Team.

3) Air conditioning during warmer months to maintain 68 – 79F.

4) Professional monitoring services to assess representative and worst-case (i.e., summer time) conditions. Both air and surface sampling protocols may be appropriate.

5) Comparison to applicable guidance values as indicated above, floor/system maintenance/hygiene protocols, awareness/training, and State & Local Health Department requirements.

The information contained in this report was obtained from sources which to the best of the writer’s knowledge are authentic and reliable. Gallagher Bassett Services, Inc. makes no guarantee of results, and assumes no liability in connection with either the information herein contained, or the safety suggestions herein made. Moreover, it cannot be assumed that every acceptable safety procedure is contained herein or that abnormal or unusual circumstances may not warrant or require further or additional procedures.