An electronic cigarette in a Delta Airlines passenger’s carry-on bag ignited Wednesday night while the aircraft was still on the tarmac, causing the flight to be delayed, the airline said.

Delta flight 689 was scheduled to depart Hartsfield-Jackson Atlanta International Airport at 7:25 p.m. and arrive in St. Louis at 8:10 p.m. local time. Instead, it departed Atlanta at 7:50 p.m. and arrived in St. Louis at 8:51 p.m. local time, according to Delta’s website.

Delta spokeswoman Ashley Black said, “During the boarding process of Delta Flight 689 traveling from ATL to STL around 7:00 p.m. Wednesday night, a customer’s bag ignited from an e-cigarette. The bag was safely extinguished with no damage to the aircraft. The

flight departed about 20 minutes past scheduled departure. It was an MD-90 aircraft with 160 passengers and 6 crew on board.”

A spokesman for Hartsfield-Jackson Atlanta International Airport, Andrew Gobeil, said the e-cigarette was inside a backpack, and there were no flames when the fire department arrived.

According to Delta’s website, electronic cigarettes are permitted on-board. The airline states, “Battery-powered portable electronic smoking devices (e.g., e-cigarettes, e-cigs, e-cigars, e-pipes, e-hookahs, personal vaporizers, electronic nicotine delivery systems) when carried by passengers or crewmembers for personal use must be carried on one’s person or in carry-on baggage only. Recharging of the devices and/or the batteries on board the aircraft is not permitted.”