The leak was confined to a small area in the basement of One Life Fitness at 4400 Montgomery Ave. in Bethesda, Fire & Rescue Service Spokesperson Pete Piringer said.
HazMat crews entered the building to assess damages as guests evacuated. Two patients were transported for evaluation, Piringer added.
The fitness center had reopened by 8:15 a.m., according to post on its social media page.
The cause of the leak was not immediately clear.
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