United flight # 1579, a Boeing 757 with 124 passengers and 7 crew members, was scheduled to leave at 9:22 p.m, reported ABC affiliate WABC.
But at 9:38 p.m. the airport tweeted, "Newark Airport is temporarily closed due to deployment of emergency chutes on a plane with an apparent engine fire. No injuries reported."
"Emergency response teams at #EWR; plane with reported engine fire," the airport tweeted at 9:55 p.m. "No reported injuries. Airport closed for passenger safety. Expect delays."
About an hour later, though, the airport was reopened, "#EWR has reopened after earlier incident of plane with apparent engine fire," the airport tweeted at 10:42 p.m. "Reports of 5 minor injuries. Expect delays remainder of night."
United said in a statement, "During taxiing of United flight 1579 from Newark to San Francisco, the tower notified the crew of what appeared to be flames from one of the engines. The crew immediately deployed the slides and evacuated the aircraft. At this time we have a report of only one minor injury. Customers are being transported back to the terminal. We are working to get our customers to San Francisco as soon as possible."
The FAA tells ABC News "flames were reported coming from the right side of the engine."
ABC News' Joshua Hoyos, Rex Sakamoto, Omar Rodriguez and Erin Dooley contributed to this report.