A series of safety issues could halt Washington D.C.'s Metro service — the second-busiest subway system in the country.
Federal Transportation Secretary Anthony Foxx said Tuesday, "The culture of safety is not where we want to see it."
Foxx told reporters he wouldn't hesitate to shut down the Metro if the transit agency doesn't take safety precautions, a move prompted by an insulator explosion last week that was caught on video.
Following the explosion, Metro officials didn't shut down stations nearby until hours later, and they made federal investigators wait several hours to inspect the tracks.
This isn't the first time the D.C. Metro trains have experienced safety issues or have been threatened with temporary closure.
Trains were shut down for a day in March as the Metro conducted "emergency inspections" following a tunnel fire.
"As situations arise, I will deal with them with the customers' safety and the employees' safety first and foremost in my mind," Metro General Manager Paul Wiedefeld said.
Last week, the Metro announced a new safety and maintenance program, but Foxx isn't sure it will make a big enough difference.
He said there's a disconnect between the safety issues and the maintenance being done.
The U.S. Department of Transportation has given the Metro until May 16 to comply with new safety mandates.