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 initiated a sampling and analysis plan for air sampling. The plan was initially provided to OSC Vega on the evening of August 2, 2007. The plan was reviewed by personnel from the U.S. EPA Region II Emergency Response Team (ERT), U.S. EPA Region 5, and the Minnesota Pollution Control Agency (MPCA). On August 3, 2007, the plan was revised throughout the day to incorporate the group’s comments and changing needs. At 1730 hours on August 3, 2007, the MPCA communicated to the U.S. EPA that access had been obtained/granted to conduct the air analysis. U.S. EPA, and START mobilized to the site at 1830 hours to begin collection of air samples.
Three air sampling locations were selected and are been sampled and monitored by the START contractor. The exact locations for the three samples are: 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 winds are pretty calm tonight, but these locations were selected based on prevailing wind direction.
The three sampling locations will be analyzed for lead, asbestos, and silica in air. In addition, two locations will to be analyzed for volatile organic compounds (VOCs). No VOC sample is been taken at the 10th Avenue Bridge location due to high vehicular traffic and the placement of light plants on the bridge.
VOC and asbestos samples will be dropped off at local laboratories on Saturday morning for analysis. The lead and silica samples will be shipped via overnight courier for delivery on Monday morning.
None at this time.
Complete the initial sampling at three project sampling locations for lead, asbestos fibers, silica, and VOCs.
Receive and review the asbestos and VOC results late Saturday afternoon August 4, 2007
Receive and review the lead and silica analytical results late Monday August 6, 2007 or first thing the morning of Tuesday of August 7, 2007.
Make further commendations based on initial assessment results.
The Incident Commander has not released much of the area surrounding the collapse site due to structural concerns and ongoing recovery operations. Sampling locations may be based more on accessibility then ideal sampling locations due to access restrictions.
Severe weather is projected to move into the area on Saturday. This could hamper any additional sampling and may raise the water level in the river.
The President of the United States is expected to visit the collapse site on Saturday August 4, 2007. The time and duration of the visit is unknown. Secret service activities focusing on the President’s visit could impact sampling locations and sample run time.
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