U.S. authorities were searching at least four Midwestern states Friday after more than 500 pounds of dangerous, commercial-grade fireworks were stolen from a freight train this week.

An unidentified law enforcement source told CBS News the theft has raised significant concern that the fireworks could fall into the wrong hands. Commercial-grade fireworks are illegal to either own or use without a permit and are typically handled only by professionals.

The explosives were stolen from a CSX freight train somewhere between Chicago and Detroit. When the train arrived in the Motor City, one-half of the volatile load was missing, amounting to at least 32 cases. The theft was reported to authorities Wednesday.

The cache includes 2.5- and 5-inch aerial fireworks commonly used in public displays on the Fourth of July and New Year’s Eve, ABC News reported.

The Detroit field office of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives was overseeing a search across Illinois, Indiana, Michigan and Ohio. The ATF was considering issuing an advisory and offering an award for the recovery of the fireworks. Meanwhile, it has set up a tip phone line at 313-202-3400.

Authorities indicated they believe that a number of people were involved in carrying out the theft. The quantity of the explosives stolen in this week’s heist has piqued the interest of federal authorities, but the theft isn’t unprecedented.

Louisiana authorities in 2014 charged two men with the theft of 20 cases of commercial-grade fireworks destined for a New Year’s Eve celebration in Bossier City.