On March 3, 1991, Line 3 of the Lakehead Pipeline Company burst near Grand Rapids, Minnesota. An estimated 1.7 million gallons of oil spilled into the nearby Prairie River and surrounding wetlands, making it the largest inland oil spill in US history.
Line 3 was built in the 1960s by the Lakehead Pipeline Company to transport oil from Canada to the Midwest. It passed east of Grand Rapids, Minnesota, near the Prairie River. On March 3, 1991, the thirty-four-inch pipeline ruptured along a small crack, resulting in a five-foot-long gash in the pipe. The pressurized oil shot into the air, immediately covering the surrounding trees and spilling into the Prairie River and the nearby wetlands.
At 12:40 p.m. a local resident reported a strong oil odor to the fire department, which immediately notified Lakehead. The company turned off the line at 1:30 p.m. Between two and three hundred residents who lived near the spill site were evacuated for the remainder of the day, and Highway 169 was closed east of Grand Rapids for several hours due to proximity to the spill.
Lakehead initially estimated that about 630,000 gallons of oil had spilled as a result of the ruptured pipe, but they nearly tripled the estimate later to 1.7 million gallons of oil. Marshes and vegetated riverbanks were the primary environment affected by the spill, and samples were taken of river water, groundwater, and well water to determine the extent of the damage. Several fish died where oil first entered the water stream, but there were few other wildlife impacts.
Because the Prairie River is a tributary of the Mississippi River, the repercussions could have been far-reaching, but several factors limited the harm. Cold air temperatures made the oil viscous, so it moved more slowly than it would have in warmer months. Additionally, the Prairie River was covered by eighteen inches of ice, which barred much of the oil from entering the water stream. The frozen ground limited the amount of oil absorbed into the soil, and the absence of migratory birds prevented extensive wildlife impact.
The cleanup effort took several months and cost millions of dollars. Steve Wuori managed the onsite cleanup for Lakehead, supervising about ninety people from several Midwest states. Crews worked around the clock in twelve-hour shifts, except when temperatures were too cold to safely operate machinery, and employed several methods of stopping and recovering the spilled oil.
Downriver from the spill, personnel cut large slots in the ice with chainsaws to install booms in the water, preventing oil from spreading to the Mississippi River. Large berms of absorbent material were built on top of the ice to absorb any oil still sliding downstream on the surface. Personnel pushed the oil across the ice with squeegees to designated collection points, where vacuums removed it. Oil-permeated ice was cut into moveable blocks and taken to an unaffected part of the river. Crews sprayed the blocks with warm water, releasing the oil and recovering it with skimmers. Ice that was only slightly contaminated was removed from the river and set to thaw in lined holding ponds. Once the ice had melted, the oil was recovered from the ponds. Governor Arne Carlson visited the spill site during the cleanup and commended Lakehead on its efforts and cooperation with state officials.
After the initial cleanup was complete, Lakehead built a pond near the spill site to collect runoff as the ground thawed and released more oil. By June, Lakehead had spent seven million dollars on cleanup, and they petitioned for a permit to release the water from the holding pond into the Prairie River.
Twenty-five locals who lived near the spill site unsuccessfully opposed granting the permit, arguing that doing so would release the company of responsibility for the damage, as well as increase the amount of environmental harm. The Minnesota Pollution Control Agency countered that additional damage to the ecosystem was unlikely at that point, and maintained that the water met state quality standards. The board granted the permit to release the water once all of the petroleum compounds had sunk to the bottom of the pond and the volatile compounds had evaporated. The draining of the pond was the final step in Lakehead’s cleanup process after the Line 3 spill.