Niagara Mohawk Power Corporation is expected to do the work and pay for the $6.5 million final phase of the cleanup.
The EPA issued its first cleanup plan for the so-called Excelsior site in 1995. It found contaminants in the ground water and soil on the Niagara Mohawk property, at a former skating rink, in stream sediment, and the former Spa Steel property.
During the first cleanup, contaminated soil and sediment were removed from areas containing coal tar waste.
Similar cleanups at former manufactured gas plants have been going on for decades in New York and other states.
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