Half of a collapsed railroad bridge connecting South Dakota and Iowa was demolished in a controlled demolition on Monday, part of the process to remove the bridge months after it collapsed into the river swollen by severe flooding.

NORTH SIOUX CITY, SD — Half of a collapsed railroad bridge connecting South Dakota and Iowa was blown up in a controlled demolition, part of demolition efforts months after the bridge collapsed into the river swollen by severe flooding.

The steel bridge over the Big Sioux River connecting North Sioux City, South Dakota, to Sioux City, Iowa, was partially submerged after heavy rains in late June caused the river to reach record highs in the two states, as well as in Minnesota and Nebraska.

The explosion on the South Dakota side of the bridge, owned by BNSF Railway, occurred Monday morning, Sioux City, Iowa, television station KTIV reported. Officials set up an exclusion zone on both sides of the river, closed surrounding roads and advised people to stay away.

“At 9 a.m. local time, the bridge section was successfully cut into sections using explosive charges so that it could be dropped into the river and removed,” Kendall Sloan, BNSF communications director, said in a statement.

“Given the condition and location of the defective bridge sections, a controlled demolition was the safest method of removing them,” Sloan added.

Sloan said workers will use a crane to remove the fallen pieces over the next week and that a second controlled demolition is expected to take place on the Iowa side of the bridge in September.

Amy McBeth, BNSF’s public relations director, told KTIV that the controlled demolition had to be done in two parts because a dam was needed on both sides to get the heavy equipment close to the river.

The design process for a new bridge is underway and reconstruction is expected to take approximately nine months.