Dangerous readings across several buildings

Nashville fire crews evacuated 53 units at an apartment complex in Antioch early Saturday after responding to a carbon-monoxide alarm at 215 Ben Hill Drive, fire officials said. Testing found dangerous levels of natural gas and carbon monoxide in multiple buildings, including the building where the alarm originated.

All 36 units in that building were evacuated. Four nearby townhome buildings were also largely self-evacuated, bringing the reported total to 53 units. WSMV separately reported that crews tested five additional buildings and detected high natural-gas levels in each. No injuries were reported, and WTVF NewsChannel 5 said no residents required assessment by medical crews.

Construction activity examined

The Nashville Fire Department said its preliminary theory centers on a construction area uphill from the apartments where drilling or blasting had created multiple bore holes. Officials said they consulted a geologist and believe underground gas, possibly from a methane pocket, may have been disturbed by work at the site.

According to the fire department, Spire responded and confirmed the incident was not a leak from the commercial gas system. Officials warned that the gas lacked the odor additive used to signal commercial leaks and could therefore be undetectable by smell while still posing a health risk at certain concentrations.

Return timeline remains unclear

Fire officials said readings had fallen slightly but were holding steady rather than fully dissipating. The department contacted the company overseeing the nearby project, which was expected to dig a trench intended to ventilate the gas. Officials said they did not know when that work would begin or how effective it would be.

Crews estimated that clearing the gas could take as long as three days, leaving residents facing an uncertain return and possible need for alternative accommodation. The apartment clubhouse was available as shelter for residents who had not left, although most had already departed, WTVF NewsChannel 5 reported.