A portion of the Brothers to the Rescue Park in Coral Gables is closed after officials found toxic ash in the soil.
Miami-Dade County's Division of Environmental Resources Management spokesman Luis Espinoza says early soil tests showed levels of dangerous heavy metals that are just below the threshold for hazardous chemicals.
The Miami Herald reports the county decided to fence off affected areas of the park until further testing could be done.
Workers first reported the issue in late December. Espinoza says they are devising a plan to address the issue.
The park is divided into four baseball diamonds and hosts various baseball leagues.
An incinerator once operated just south of the park.
Officials say soil testing could take three weeks.