A preliminary report says firefighters who responded to an electrical malfunction on the Washington subway system had difficulty communicating by radio and some had to use cellphones instead.

The city released a report Saturday that says fire officials notified Metro officials of a problem with radio coverage in the L'Enfant Plaza station on Jan. 8, four days before the malfunction near the station. An email attached to the report suggests Metro was doing work on the system but believed it was back online in the station, though problems in the tunnel continued.

The report says the radios could still function as walkie-talkies, but one firefighter wrote that radio communications were "nonexistent" in the tunnel.

One person died and more than 80 were taken to the hospital during the incident Monday.