On May 2, 2007, the Missouri Department of Natural Resources (MDNR) requested that the U.S. Environmental Protection Agency (EPA) contact the General Services Administration (GSA) to inquire about a release of elemental mercury from a mercuric sphygmomanometer (blood pressure cuff) that had occurred in the fitness center of the RAY Federal Building in St. Louis, Missouri. MDNR was notified by the St. Louis City Health Department that a release of mercury occurred during the afternoon of May 1, 2007, and the St. Louis Fire Department conducted a simple cleanup. EPA maintains a Lumex® model RA915+ portable mercury vapor analyzer (MVA) in the St. Louis Metropolitan area with the ability perform mercury vapor analysis. MDNR requested the EPA assess the adequacy of the cleanup.
GSA granted access for EPA to perform assessment activities at approximately 1345 hours on May 2, 2007. EPA and MDNR responded.
Background concentrations of mercury vapors taken prior to EPA entering the RAY Federal Building on May 2 were approximately 80 nanograms per cubic meter (ng/m3). Light rain was falling at the time the background sample was taken and may have affected the background readings.
An initial reading inside the fitness center was taken at the south entrance. Mercury vapor levels were recorded to be approximately 362 ng/m3 at that location.
The spill area was centrally located on the west side of the fitness center. A blood pressure cuff mounted to the wall about 3 to 4 feet from the floor was the spill source. The mounting bracket identifying the former location of the blood pressure cuff was still fastened to the wall at the time of the inspection. An equipment cart loaded with a broken fitness machine was located directly under the mounting bracket. The floor of the fitness center was a nonporous, permanently affixed rubber mat with a pre-molded traction pattern.
Mercury vapor levels were 866 ng/m3; 1,500 ng/m3; and 1,183 ng/m3 on and around the equipment cart. A mercury vapor reading of 22,000 ng/m3 was recorded approximately one inch off of the floor directly above the spill area near the wall.
EPA and MDNR conducted a visual inspection of the area. Small “micro-beads” of mercury were visible on the floor, equipment cart, and against the wall.
Due to the elevated levels of mercury vapors and the identification of mercury beads on the floor and equipment cart, EPA recommended to that additional clean-up activities were needed. GSA agreed and asked the EPA to assist.
EPA utilized a Nikro Industries model MV00688-SS mercury recovery vacuum to physically remove mercury remaining on the floor and cart. EPA then moved the cart outside so that any remaining mercury could be ventilated. EPA then scrubbed the floor of the fitness center with HgX®, a mercury decontamination compound. The MVA indicated mercury was present behind the baseboard at the floor directly under the former location of the blood pressure cuff. EPA removed and disposed of the baseboard and vacuumed the exposed area.
At approximately 1700 hours the Heating, Ventilation and Air-Conditioning (HVAC) system was shut down for the evening.
On the morning of May 3, 2007, the EPA returned to determine if any sources of mercury remained and if vapors were adequately vented. MVA readings taken during the follow-up visit are represented in the following paragraph:
|Area Sampled||Mercury Concentration Recorded|
|Background (outside bldg in back parking lot)||~450 ng/m3|
|Hall outside south entrance into fitness center||353 ng/m3|
|Kiosk near entrance to Occupational Health||362 ng/m3|
|One inch over the spill location||336 ng/m3|
|North end of track||332 ng/m3|
|East side of track||324 ng/m3|
|South end of track||329 ng/m3|
|Hall outside east entrance into fitness center||218 ng/m3|
|Men’s locker room||382 ng/m3|
|Women’s locker room||347 ng/m3|
Mercury vapor concentrations in the crack at the base of the wall where the baseboard was removed indicated the presence of micro-beads. EPA recommended to GSA that a caulk or sealant be applied to the crack before the baseboard was replaced by GSA.
Mercury vapor concentrations observed in the fitness center on May 3, 2007, were below EPA emergency response guidelines for cleanup of non-residential structures and indicated all significant source areas of elemental mercury were removed.
No further action regarding this release is planned.
No further steps are required.