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Environmental Impacts & Concerns


The 35W Bridge collapse in Minneapolis, Minnesota at 6:08pm on August 1, 2007 created instantaneous impacts on commuters, neighbors, and the surrounding physical environment.  Contruction materials and vehicles on the bridge, train cars crushed underneath the structure, pollution from historical land use, and the bridge materials themselves were all potential sources of hazardous air, water, and soil contamination.  Response efforts related to tahe environmental impacts, led by the Minnesota Department of Transportation, Minnesota Pollution Control Agency and Mississippi Watershed Management Organization, began immediately.  These agencies in cooperation with the City of Minneapolis, other agencies active on site, and private contractors identified specific concerns and began removing, testing, and monitoring mitigation efforts designed to protect the recovery and demolition workers, local and downstream populations, and the river habitat.



Preexisting Environmental Conditions



Minnesota Real Estate Board 1914 Historical Atlas featuring Gas Light plant and other heavy industry.


Historical land uses on the north and south river banks have been both dense and heavily industrial over the past 120+ years.  Fire Insurance Maps dated 1885 depict extensive south bank industrial use in the immediate vicinity of the bridge collapse site including a rail yard, the extensive Basset & Co. Lumber Yard, Globe Oil Co., Monitor Plow Works, North Star Coal piling area, and most notoriously the Minneapolis Gas Light Company coal gasification plant [22].  An 1892 atlas also shows a stone quarry on the south bank, and along the north bank are rail lines and a foundry (later shown as the American Bridge Co., and occupied through present-day as MetalMatic [30][31]) two blocks to the northwest [23].  Additional maps covering 1906-1925 show continued expansion of heavy use on the south bank in the form of the Indian Refining Company, Barret Manufacturing (roofing materials), an added rail roundhouse, and expansion on the Gas Light Co. property [24][25][26][27][28][29].  Numerous commercial and residential properties of lesser environmental concern also existed within and in the immediate vicinity of these areas.


Each of the land uses highlighted above are sources of potential historical contamination from petroluem & gas products, heavy metals, and industrial process chemicals.  Heavy industrial use in this area gradually diminished after the first three decades of the twentieth century, as technology advanced and transportation networks shifted.  Even so, this pattern of usage over many decades, far predating environmental regulation and the construction of Bridge 9340 in the 1960s, has left numerous known contamination sites and probable Recognized Envionmental Conditions (RECs).

"The term recognized environmental conditions means the presence or likely presence of any hazardous substances or petroleum products on a property under conditions that indicate an existing release, a past release, or a material threat of a release of any hazardous substances or petroleum products into structures on the property or into the ground, ground water, or surface water of the property." [8]



Collapse-related Environmental Impacts


Physical Disturbance

The collapse of the bridge created immediate damage to vehicles on the structure at the time, to rail cars below the bridge, and disturbance to the ground below the bridge.  Bridge debris and construction materials being stored on the bridge deck were also deposited in the Mississippi River, causing flow and possible habitat disruption, and potential contamination risks.  Local, state, and federal agencies worked to identify, monitor, neutralize, and eventually remove the sources of all these potential risks. [1][2][4]


Potential/Actual Toxic Releases

Based on both standard environmental practices and on lessons learned from previous disasters, monitoring and testing directed by the MPCA, MWMO, and US EPA was conducted for a wide array of possible air and water pollutants[4].  Particular point sources and contaminants were suspected and targeted using several up- and downstream monitoring stations - see Table 1.



Table 1. Potential contaminants monitored, by medium.

Air Asbestos, VOC, TSP (Total Suspended Particulates), silicates, and heavy metals including mercury and lead [4][6]
Water Petroleum products (included VOC), heavy metals including mercury and lead, asbestos, PCBs, and deicing chemicals [2],



Hydrologic Impacts

Sampling of the Mississippi River water was conducted by the MWMO from August 2 through October 3, 2007.  Using a baseline set of water quality data derived from previous routine sampling results, the watershed organization and MPCA determined that state water quality standards had not been exceeded following the collapse, nor throughout the recovery period.  By October 15, debris removal had been completed and the intensive sampling was discontinued.  As of March 2008, expanded sampling has not been renewed, though the MWMO remains in discussion with state agencies regarding the the potential need for additional sampling or other efforts related to long-term impacts on the aquatic habitats impacted by the bridge collapse.[2]


In the week following the collapse, the MWMO along with Mn/DOT personnel also assessed the extent of the damage and debris on the 35W Bridge site, and evaluated the impeding demolition and excavation requirements.  With this analysis, a Stormwater Pollution Prevention Plan (SWPPP) [11] was developed to ensure the best possible protection of the river waters from the impending debris removal and cleanup work on both banks.  Best Management Practices (BMPs) were specified for all anticipated points of possible runoff and soil deposition, for both the bridge site and the materials staging/recovery area at the Bohemian Flats.  The SWPPP was revised several times through September 2007, and followed up with additional inspections and testing in October.  Most protection measures were deemed successful throughout the demolition period, with some relatively minor problems corrected as identified by inspection.[13]


In sum, after extensive sampling and monitoring, no environmental impact of concern was identified in the waters of the Mississippi River following the collapse of the 35W Bridge, and through the subsequent recovery and debris removal activity.


Air Quality Impacts

The US EPA's Region 5 director met with MPCA representatives very shortly after the collapse, and highlighted the need for timely air quality testing, informed by the health impact lessons learned after the events of 9/11/01 in New York City.  Subsequently, private contractors for the EPA conducted air sampling from August 10-12, 2007.  This round of sampling was used to establish a baseline of air conditions around the site prior to the start of demolition activities, which would

generate more serious air quality concerns than the collapse itself.  Analysis by EPA, MPCA, Minneapolis Environmental Management, and the Minnesota Department of Health identified no health hazards or unusual concentrations of any of the sampled materials.  All measurements were within the normal range expected by urban ambient air quality standards.[4][6]


A second round of air quality testing was performed from August 27 through 31, simultaneous to the heaviest demolition and excavation operations.  At the sampling location closest to the demolition activities, elevated levels of suspended particulates were detected on August 28, and although not considered a health concern at that time, recommendation was made to make greater efforts to control the dust being created.  No other conditions of concern were identified on any other dates or at any other sampling locations.[4][6]


With no further activity potentially generating airborne pollutants or excessive dust, event-specific air quality monitoring has not continued.  The end result of the EPA-initiated testing was slightly elevated particualtes in the immediate vicinity of demolition activity for approximately one day, and overall no notable risk to human or environmental health.



Health & Habitat Risks Since Bridge Collapse


Basic demographics of immediate vicinity

According the US Census FactFinder, no residential populations exist in the blocks directly impacted by the collapse of the 35W Bridge on both north and south banks.  However, dense student and other poulations reside in the surrounding blocks on the north bank.  Please see the Chronology and Victim Compensation pages for more details on the immediate victims of the structural collapse.


Public Health And Safety Regarding Spills

The Minnesota Pollution Control Agency (MPCA) was one of the agencies monitoring the immediate health and safety of the public by looking for spills.  Workers scoured the Mississippi for petroleum primarily.  They concluded that there was no immediate threat from anything that was spilled.  Among the items that were crushed or had lost contents to the Mississippi, were three rail cars which held platic pellets, plastic powder, and ethanol. [7]


Mental Health Counseling

Counselors from the county's mental health department helped survivors deal with emotional fallout from the traumatic event.  The Hennepin county children's health services had been working on a disaster response plan, and were ready to implement its use after the collapse of the bridge on August 1.  The county was thought to have the deepest resources and best staff for taking the initiative in reaching out to traumatized individuals that witnessed the tragic event or were victims of it.  Volunteers from local non-profits and private mental health facilities worked with families that were immigrants and spoke English as their second language to provide emotional support and counseling. [14]


The Minnesota Department of Health set up information on their home page emphasizing current events from the bridge collapse, recruiting volunteers that want to contribute, and providing individuals with the chance to recover mentally and physically by listing mental health services links on their home page.


Habitat Surrounding Bridge Collapse

MnDot agreed to preserve three historic properties near the bridge collapse that included the 10th Avenue bridge, the Lower Saint Anthony Falls Lock and Dam and a stone retaining wall on the north side of the river.  The Higgins Eye pearly muscle is a federally protected endangered species that does not live in the direct vicinity of the bridge but five miles downstream near the Ford Dam in St. Paul.  The U.S. Fish and Wildlife Service claimed that the reconstruction of the bridge would have no effect on the muscles or any other critical habitat as long as there were not any peculiar sediments or toxins released into the water.  MnDot is supposed to inform the U.S. Fish and Wildlife Service immediately if that were to happen. [32]



Regulatory Issues & Concerns


Bridge Inspections

After the bridge collapse it was brought to the attention of governor Tim Pawlenty that many people were concerned that other bridges were potentially unsafe, so he ordered a statewide bridge inspection that examined more than 4,000 bridges during a five-month period.  Inspectors reported that there were only 17 findings and of those only 6 required immediate action.  Lowering weight limits and restricting traffic, were a couple of the actions required for repairing the bridges. [15]


The American Road & Transportation Builders Association (ARTBA) addressed concern when the Federal Highway Association (FHWA) noted that of the 594,709 bridges in the United States, 152,945 were structurally deficient.  The motoring public was not impressed with the description that defined "structurally deficient".  Structurally  deficient  to ARTBA is interpreted as "[bridges] left open to traffic, typically require significant maintenance and repair to remain in service." [19]



A $15 million dollar debris-removal plan was set in action to clear the vehicles and rubble from the bridge collapse.  Each piece of rubble extracted from the river was inspected to map the location of the debris field.  The plan was a lengthy process which halted the rebuilding phase. No work on the replacement bridge took place until the debris field was completely cleared.  The plan also drained funds from other state projects. [16]  Governor Tim Pawlenty also notioned that he supported the idea of a light rail that extended across the Mississippi.


Carl Bolander And Sons was the main company in charge of the 35W bridge removal project.  They coordinated and delegated responsibilities out to twenty different local, state, and federal subcontractors.  The crews removed 4,000 tons of steel, 10,000 tons of concrete, and dozens of cars from the Mississippi.  The removal plan was finished in the middle of October, almost 2 1/2 months after the collapse.  The cost weighed in at $8 million, which was almost 1/2 what the original budget was set at.  The crews and subcontractors under Carl Bolander & Sons had 60 people on site working 12 hours a day, 6 days a week with a final work load yield of 32,000 hours of labor. [21]


Transportation Impacts

Since the collapse of the 35w bridge, other routes have been devised, however they are not as short as the bridge route, therefore more gas emmisions are released into the environment with longer routes.  In light of the FHWA statistic that states that 26 percent of the United States 594, 709 bridges are structurally deficient, coincides with the fact that there are increasing numbers of frustrated commuters and truckers that haul freight when traveling across the aged infrastructure.  The Texas Transportation Institute has found traffic bottlenecks costs the U.S. economy more than $65 billion each year in lost productivity and wasted motor fuel, and tend to add tons of greenhouse gas emissions into the atmosphere which in turn makes the goal of energy independence even tougher. [9]


Traffic Impacts

Traffic Congestion in the twin cities increased shortly after the bridge collapse.  Many people including students were concerned with alternate routes not being feasible to their schedule and impairing their transportation to and from classes.  A study showed that in 2006 there was only 267 miles of congested highway as compared to 305 miles this year. The bridge was a major channel through the metro highway system.  [17]


Traffic restoration projects have been a tremendous help in reducing the impact of that collapse, in terms of the amount of traffic congestion in the freeway system.  The traffic restoration projects were put into effect to add capacity, enhance traffic management that in turn would hinder bottlenecks. 

  • I-94 added an additional lane to accomodate traffic from I-35W.

  • Highway 280 has become a freeway and is a part of the I-35 detour. [18]



Traffic Backed Up After Bridge Collapse Due Taken By Darcy Karue (Flickr profile:  darcykayrue)



Transit Response Plan

The 35W Bridge Response Plan intended to increase its express bus service by increasing the number of buses and hiring more mechanics and operators that would drive the routes of the newly added park-and-ride spaces in the north and east metro.  Federal funding of $5 million was expected to pay for the 55 additional buses.  Of the new buses, 18 of them would be hybrid, which is part of the Metro Transits Go Greener Initiative, to help decrease gas emmissions and support clean air quality.  Since the bridge collapse greenhouse gas emmissions have been steadily increasing with the traffic that has been building up due to bridge collapse, and the hybrid buses will alleviate some stress placed in that area.  However, immediately afer the collapse 25 buses were deployed to supplement north-metro park-and-ride locations.  This service also offered free bus rides to 12 park-and-ride locations.  Highway 610 and Noble and I-35W and 95th Avenue had park-and-ride facilities that were increased north of downtown Minneapolis.  The agency also encouraged business and community leaders to use the transit line and carpool as much as possible. [20]




See Also:


Vehicles involved in the collapse

Technical Response Efforts

Carl Bolander And Sons

10th Avenue bridge

Lower Saint Anthony Falls Lock and Dam




1. Environmental Checks Near the Site.City of Minneapolis. Retrieved 3.9.08

2. Environmental Response to the I-35W Bridge Collapse.  Mississippi Watershed Management Organization. Retrieved 3.9.08

3. Interstate 35W Bridge Rebuild - Environmental Review. Minnesota Department of Transportation. Retrieved 3.9.08

4. Levy, Steve. “Sampling & Monitoring in Emergencies & Disasters.” MPCA Air, Water, & Waste Environmental Conference. Bloomington, MN. 2.27.08.

5. Interstate 35W Bridge Collapse. Minnesota Department of Transportation. Retrieved 3.9.08

6. Air Monitoring City of Minneapolis. Retrieved 3.9.08

7. Birkey, Andy. Agencies Monitoring Environmental, Health Risks since Bridge Collapse. Minnesota Monitor 8.8.07

8. ASTM E1527-05 Standard Practice for Environmental Site Assessments.

9. Ruane, Peter  Highway To A National Vision

10. Best Management Practice. Wikipedia. Retrieved 3.13.08

11. Stenlund, Dwayne. I-35W Stormwater Pollution Prevention Plan. Mn/DOT 8.9.07.

12. Annual Monitoring Report 2006.  Mississippi Watershed Management Organization 6.28.07.

13. Stenlund, Dwayne. Mn/DOT 10.14.07. Retrieved on 3.19.08 Inspection Compilation Report. 

14. Taylor, Charles. Retrieved on 3.18.08 Hennepin's Disaster Preparedness.Mental Health Counseling.

15. Mn/Dot 12.21.07 Retrieved on 3.18.08 News Release

16. Morrissey, Ed. 8.6.07 Retrieved on 3.19.07 Captain's Quarters

17. Randolph, Toni. 3.16.08 MPR Retrieved on 3.15.08 Increased Traffic Congestion

18. Mn/Dot Retrieved on 3.17.08 Traffic Improvement

19. Wagner, Hole. 9.10.2007 Retrieved on 3.16.08  Bridge Collapse Spurs Concern

20. 11.29.07 Retrieved on 3.16.08 Metropolitan Council

21. Johnson, Brian. 2.11.08 Retrieved on 3.16.08 Finance And Commerce

22. Fire Insurance Atlas of Minneapolis. Vol. 1, Plates 4 & 35.  Maps.  Chicago: Sanborn, 1885.

23. City of Minneapolis, Minnesota. Plates 10 & 11.  Maps.  Minneapolis: C.M. Foote & Co., 1892.

24. Atlas of Minneapolis, Minnesota & Suburbs. Vol. 4 & 5.  Maps.  Rascher Insurance Maps Publishing Co., 1906.

25. Fire Insurance Atlas of Minneapolis. Vol. 3, Plate 240 and Vol. 8, Plate 960.  Maps.  Chicago: Sanborn, 1912.

26. Atlas of Hennepin County, Minnesota. Map. Minneapolis: Minneapolis Real Estate Board, 1914.

27.Fire Insurance Atlas of Minneapolis. Vol. 3, Plate 240 and Vol. 8, Plate 960.  Maps.  Chicago: Sanborn, 1925.

28. Atlas of the City of Minneapolis, Minnesota. Map. Minneapolis: Minnesota Works Project Administration, 1940.

29. Fire Insurance Atlas of Minneapolis. Vol. 3, Plate 240 and Vol. 8, Plate 960.  Maps.  Chicago: Sanborn, 1952.

30. Minneapolis Polk City Directory.  Chicago: R. L. Polk, 1930, 1935, 1940, 1946, 1952, 1957, 1962, 1966-67, 1972, 1977, 1981-2, 1987, and 1993.

31. Minneapolis Cross-Reference Directory. Lincoln, NE: Cole Directory, 2000-01.

32. Scheck, Tom. 10.14.07 MPR Retrieved on 3.22.08 Cost To Rebuild 35w

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