Carlsbad Caverns National Park has reopened after “extensive” air quality testing showed that chemical vapors released during elevator renovation had not spread to the visitor center or surrounding cave areas.
The caverns and visitor center in the park were closed and the work halted about 2 p.m. Monday (July 23) after “overpowering” odors from an elevator renovation project left employees with severe headaches, the park superintendent said.
National Park Service
|Renovation of the caverns’ two primary elevators is a complex project that included renovation of the twin Dover G250 motors installed in 1976. The motors have powered the two cars on more than 1.6 million trips on the 750-foot journey down into, and back out of, Carlsbad Cavern. |
The employees were treated at area medical facilities and released.
Coating, Solvent Identified
The products in use at the time were an immersion-grade epoxy and the solvent methyl-ethyl-ketone, park spokeswoman Paula J. Bauer wrote in an email.
The epoxy is used to provide corrosion protection in maintenance and new construction projects. The product can be used direct to metal as a corrosion-resistant primer or as an intermediate coating over other primers, according to the manufacturer.
Wikimedia Commons / Eric Guinther
|The vapors did not spread to surrounding caves or to the Visitor Center, the Park Service said.|
Both parts of the product are flammable, contain silica, and are harmful if inhaled, according to the MSDS.
Methyl-ethyl-ketone, also known as butanone, is a common industrial solvent.
The Park Service declined to say exactly how the products were being used or what contractor was performing the work.
The park brought in industrial hygienists Tuesday (July 24) to test the air quality, superintendent John Benjamin said in a prepared statement.
"Three industrial hygienists toured the building this morning and tested air quality with two separate sets of instruments," said Benjamin. "With their precise test results and after consultation with safety experts, we are confident the air quality is safe for visitors and employees."
After the park service received the test results Wednesday morning, the caverns and visitor center reopened at noon that day.
About the Project
The ongoing renovation of the caverns’ primary elevators began July 16 and is a complex project, the Park Service said. The vapors became a severe problem by the first weekend and were “overpowering” by July 22, said Benjamin. Ventilation efforts failed to dispel them.
Carlsbad’s original 750-foot deep elevator shaft was drilled in 1931, and the elevator opened in 1932. Two larger elevators and another shaft were added in the 1950s. Some of the elevators are used for freight; others, for passengers.
Park officials said they don't believe the fumes affected the cave or its wildlife, but staff will continue to monitor all areas.
The Park Service will provide ongoing updates at (575) 785-2232.