On August 1, 2007 at approximately 1800 hours, the I-35W Mississippi River Bridge in Minneapolis, Minnesota collapsed from abutment to abutment, falling into the Mississippi River. The I-35W Mississippi River Bridge (Bridge 9340) was an eight-lane, 1,900 foot deck-arch-truss bridge that spanned the Mississippi River. The north-south bridge connected the Minneapolis neighborhoods of Downtown East and Marcy-Holmes. The bridge was opened in 1967, was 1,907 feet in length, 108 feet wide, and had a clearance below of 64 feet. To avoid interference with river naviation, the I-35W bridge had no piers built into the river bed. Instead, the center span of the bridge consisted of a single 458-foot steel arched truss over the 390-foot wide navigation channel. The north abutment of the bridge was anchored northwest of the University of Minnesota East Bank campus. The south abutment was anchored just northeast of the Minneapolis Metrodome.
The bridge was reportedly Minnesota’s second busiest bridge, carrying an average of 141,000 vehicles a day. As a result of the bridge failure, reports indicate that more than 50 vehicles went into the river. Several vehicles, including a semi-trailer truck caught fire. In addition a portion of the bridge collapsed onto three empty freight train cars that were sitting below the bridge. To date, there are five people confirmed dead, over 100 injured, and an unknown amount of people are still missing. On Thursday August 2, 2007, the U.S. Army Corps of Engineers lowered the river level using the Ford Dam (located about 3 miles downriver at West River Road and East 50th Street) by two feet to allow easier access to vehicles in the water. Emergency responders are on-site conducting diving and recovery operations. Recovery operations could extend through the entire weekend.
Under the direction of U.S. EPA OSC Sonia Vega, the Weston Solutions, Inc. (WESTON®) Superfund Technical Assessment and Response Team (START) along with their team subcontractor Bay West conducted air sampling and monitoring, per the Minnesota Pollution Control Agency's (MPCA)request.
Three air sampling locations were selected and were sampled and monitored by the START contractor. The exact locations for the three samples were : The 10th Avenue Bridge; The roof of a University of Minnesota building located at 830 River Flats, NW corner of the collapsed Mississippi River Bridge; and the third location was about 40 yards from the collapsed brige, on south west corner. The sampling pumps ran for 8 hours, and filters were collected and sent for analysis by 0748 this morning.
The three sampling locations were analyzed for asbestos, and two locations were analyzed for volatile organic compounds (VOCs). No VOC sample was taken at the 10th Avenue Bridge location due to high vehicular traffic and the placement of light plants on the bridge. The analysis for lead and silica will take place on Monday, and we should get result by the end of the day. Results for the asbestos and VOC samples were submitted to the MPCA by 2100 hours.
Continue supporting the MPCA, as needed.
Evaluate the sampling results for lead and silica, expected by close of business Monday.
Provide any assistance and/or expertise the local governments might need.
Collaborate with the MPCA with future monitoring and sampling needs during the removal operations at the collapsed bridge site. MPCA understands the need for air montoring during the demolision process both on the demolision area and the surrounding neighborhoods.
We will meet with the MPCA staff on Monday morning to evaluate future sampling needs.
None at this time.
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