HVAC systems are effective in controlling vapor levels in gymnasiums with rubberized flooring

Precautions planned for gym floors
Posted on 08/10/2018
Rubberized gym floor

Friday, August 10, 2018

Board directs periodic air-quality monitoring
at four schools to address gym floor concerns

BEAUFORT – The Beaufort County Board of Education today directed periodic air-quality monitoring in four school gymnasiums with rubberized flooring that emits small amounts of mercury vapor.  Expert contractors who tested the air quality in all four gyms said mercury vapor levels, while detectable, were not dangerous to students or staff.

The Board decided to install protective coverings at school gyms that need it, and district officials also plan to ventilate all four gyms more frequently and monitor their cooling and heating systems more closely.

Andy Rowland, national manager of Terracon, the company that conducted air-quality testing at all four schools last week, presented a detailed report of those tests to the Board of Education today and described the mercury vapor levels as extremely low.

Rowland told news reporters that his wife had been a teacher for 32 years, and his daughter had been a teacher for four years. “Would I feel completely safe with them in this setting, and would I feel safe about my own child or nephew or niece?  The answer to those questions is yes.”

The four affected schools are Beaufort Middle School, Hilton Head Island School for the Creative Arts, Islands Academy and Robert Smalls International Academy.

District officials first became aware of the issue because Hilton Head Island School for the Creative Arts was scheduled for replacement.  The flooring contractor noted the composition of the existing gym floor and pointed out that similar rubberized floors in other states had raised air-quality concerns.  A subcontractor tested the floor and detected the presence of mercury.  Subsequent air-quality testing found a detectable quantity of mercury vapor in the gym.

The district then identified three additional schools as having gym floors manufactured using similar material.  Air-quality testing was conducted in the gyms at all four schools: Beaufort Middle School (constructed in 1985), Hilton Head Island School for the Creative Arts (constructed in 1988), Islands Academy (constructed in 1972) and Robert Smalls International Academy (constructed in 1984).  Testing was done on the same days using the same equipment. 

Very low mercury vapor levels were detected at all four sites, with levels that did not exceed safety standards so long as heating and air-conditioning (HVAC) systems were operating normally.  If HVAC systems were shut down, mercury vapor levels rose to levels still acceptable under federal standards but higher than the more stringent long-term exposure limits set by the state of Minnesota.  Once HVAC systems were restored, vapor levels decreased to levels that where safe under the most stringent standards.

Mercury is a metal that exists in liquid and vapor form, and it occurs naturally in the environment.  It also is commonly used in many consumer products, including dental fillings, and is typically encountered in homes, schools, hospitals, offices and industrial workplaces.  Beginning in the 1960s and extending into the 1990s, many manufacturers included mercury in their rubberized gym floor products to help keep the rubber flexible.  But the material breaks down over time and can release mercury vapor, which is odorless and colorless.

Breathing mercury vapor is harmful because it can be absorbed by the lungs and is not excreted from the body as solid or liquid waste.  Mercury vapor can damage the central nervous system, kidneys, lungs, skin and eyes, and is especially harmful to young children and fetuses whose bodies are still developing.  Children and pregnant (or soon-to-be pregnant) women are the most vulnerable.  The risk varies depending on how much mercury vapor a person is exposed to, how long and often a person is exposed, and his or her age and health status. 

The federal government and a handful of states have set standards for safe levels of mercury.  At the federal level, some of the most comprehensive standards have come from the Agency for Toxic Substances and Disease Registry (ATSDR), part of the U.S. Department of Health and Human Services.  ATSDR protects communities from harmful health effects related to exposure to natural and man-made hazardous substances.  ATSDR’s acceptable level of mercury vapor concentration in schools is 3,000 nanograms (parts per billion) per cubic meter. 

The Minnesota Department of Health (MDH) has published guidance specific to school gym flooring.  MDH recommends that the general public should not be exposed to short-term (one hour) mercury vapor concentrations above 1,800 nanograms per cubic meter. This conservative criterion protects all people, including sensitive individuals such as pregnant women and children.  For longer-term exposures, MDH recommends that gym teachers should not be exposed to more than 750 nanograms of mercury vapor per cubic meter during 40-hour work weeks averaged over the school year. Children exercising in the gym have greater respiration rates than teachers. Therefore, MDH says their exposure should be limited to 750 nanograms per cubic meter during 16 hours or less per week averaged over the school year.

During air-quality testing at the four Beaufort County schools last week, initial readings were taken with each school’s HVAC systems operating normally:

  • Beaufort Middle – 170 nanograms per cubic meter
  • Hilton Head Island School for the Creative Arts – 200 nanograms per cubic meter
  • Islands Academy – 440 nanograms per cubic meter
  • Robert Smalls International Academy – 670 nanograms per cubic meter

Terracon performed a second set of tests with HVAC systems not operating.  With HVAC systems turned off for 12 hours, mercury vapor levels rose above the MDH safety standard (750 nanograms per cubic meter) but remained below the ATSDR safety standard (3,000 nanograms per cubic meter).  Mercury vapor concentrations began to decrease as soon as HVAC systems were turned back on.

Based on these test results, district officials concluded that each school’s HVAC system, when operating normally, effectively controlled mercury vapor at safe levels for students, staff and visitors.

In addition to the steps directed today by the Board of Education, the school district will:

  • Operate HVAC systems at all four schools with a priority on increased ventilation rather than financial efficiency.For example, thermostat levels in all four gyms will be lowered so HVAC systems will operate more frequently.The lower temperature will also reduce vaporization of mercury in the floors.Each school’s system also will be turned on earlier in the day to ensure that it has been running prior to gym use.
  • HVAC systems at all four schools will be closely monitored.If one of the schools’ HVAC systems breaks down, its gym will be closed.Once HVAC repairs have been made and normal operation restored, the gym will remain closed until it has been properly re-ventilated.
  • Retain a consulting firm to provide ongoing technical assistance.Air sampling protocols will be developed for each gym based on the consulting firm’s recommendations.
  • Recommend that any health questions from parents, teachers or staff be directed to their physicians.

No other Beaufort County School District schools have been found to have similarly manufactured floors.

The school district has created a dedicated section on its website (beaufortschools.net) with detailed information that includes a Q&A, Terracon’s complete air-quality testing reports from all four schools and a video of today’s Board of Education presentation.  The school district will communicate directly with parents and staff by e-mail and automated telephone calls, and separate sets of meetings will be scheduled with parents and staff at each of the four schools.