As a tugboat began to sink just north of the Stan Musial Veterans Memorial Bridge, a nearby tugboat heard the distress call and rescued four crew members on board Tuesday.
No crew members were injured as they evacuated the sinking boat, owned by the Osage Marine Co., and transferred to the towboat Miranda Page.
Another towboat, the John F. Walker, eventually took them to shore safely, according to the St. Louis Post-Dispatch.
The St. Louis Fire Department responded to the sinking boat with marine units, according to the fire department's Twitter account. The boat sank near where Angelica Street meets the river:
Officials used sonar to find where the boat went under, some 100 feet north of the bridge and 100 feet off the Illinois river bank.
Another tugboat sank into the Mississippi River two weeks ago near Alton, Illinois.