(CNN) -- A Texas grand jury declined to issue charges Thursday in a November 2012 deadly collision between a freight train and a parade float that killed four veterans and injured more than a dozen people, Assistant District Attorney Eric Kalenak of Midland County said.
The accident happened on November 15 during the "Hunt for Heroes" parade to honor members of the U.S. military.
The last flatbed truck in the parade was crossing the tracks when an eastbound Union Pacific train slammed into it, Midland police said.
An attorney representing Smith Industries, the owner of the truck that served as the float, identified the driver as Dale Andrew Hayden.
Civil litigation, however, is pending as the family of at least one deceased victim and several surviving victims, including one left paralyzed, are suing the railroad and Smith Industries, according to the website of the law firm Glasheen, Valles & Inderman in Lubbock, Texas.
A second suit on behalf of families of two deceased veterans was filed in Dallas against the railroad, the law firm said.
"Of the twelve families who were on the float stuck by the train, nine have filed suit," the law firm said in a January announcement.
Last year, the National Transportation Safety Board said the grade crossing warning system, which consists of a bell, lights and a gate, operated as designed, giving a 20-second warning of the train's arrival. But the truck entered the crossing and the gate lowered, tipping over flag stands on the float.
The board re-created the accident as part of an investigation.
An NTSB board member said the south traffic light at the grade crossing turned green 21 seconds before the train's arrival at the crossing, as designed, to allow traffic time to clear the crossing. At 20 seconds before the collision, the bells and lights on the mast activated, in keeping with the minimum time under federal law.
Those killed were identified as Marine Corps Chief Warrant Officer 3 Gary Stouffer, 37; Army Sgt. Maj. Lawrence Boivin, 47; Army Sgt. Joshua Michael, 34; and Army Sgt. Maj. William Lubbers, 43.
CNN's Amanda Watts contributed to this report.