"The ball of fire looked kind of like the one in Texas, the same thing," he said. "It went up probably 300 feet."
Explosions at a fertilizer plant last month in West, Texas, left 15 dead.
Scores of people on Twitter reported feeling a "shock wave" as far away as Canton, Pasadena and Bel Air. Small business owner Robert D. Wray wrote that it shook the windows on his condo in Fells Point.
A Patterson Park resident wrote: "Dogs and I all jumped. Neighbor said her curtains blew in!"
Notable Md. rail accidents
August 2012: Two teenagers sitting beside the tracks in Ellicott City were killed when a CSX train loaded with coal derailed and buried them in coal.
March 2010: Eight of the 60 cars on a CSX freight train derailed alongside Patapsco State Park, spilling plastic pellets and debris that took more than a month to clean up. No one was hurt.
December 2006: 100 homes near the border of Carroll and Howard counties were evacuated when a tanker carrying liquid ammonia derailed.
July 2002: 101 people were injured — at least six seriously — when an Amtrak passenger train en route to Washington derailed in Montgomery County.
July 2001: Sixty cars, some carrying toxic chemicals, derailed inside the Howard Street Tunnel in Baltimore, igniting an inferno that burned for days and stopped nearly all north-south freight traffic on the East Coast for almost a week. No one was killed or injured.
January 2000: A 15-year-old boy in Garrett County was killed when a train derailed and crashed through his home.