Demolition unearths legacy of toxic pollution at Milwaukee plant

The abandoned Milwaukee Die Casting plant's legacy of toxic chemical contamination is being fully revealed this year in its demolition a cleanup that could cost former operators as much as $10 million, federal and state environmental officials said.

Much of the expense will come from properly disposing of building debris and soil soaked with hydraulic fluids containing polychlorinated biphenyls, or PCBs, at the former manufacturing plant on the city's north side.

The toxic chemicals also were found in soil north and east of the old factory, near the Milwaukee River, and in a storm sewer manhole and pipe draining to the river. Storm sewers were disconnected and cleaned in 2013 in preparation for this year's work.

This is not the first time Milwaukee Die Casting's 40-plus years of producing aluminum and zinc parts for automotive and small-engine manufacturers is being overshadowed by news of the pollution it left behind.

The closed factory gained notoriety in 2007, a decade after metal casting ended, when PCBs were dislodged from a city sewer by an unsuspecting cleaning crew. The chemicals flowed downstream to the Jones Island sewage treatment plant.

PCBs contaminated tons of Milorganite fertilizer made at the plant, including thousands of pounds that already had been distributed for free to public recreational fields throughout Milwaukee County. The incident cost the Milwaukee Metropolitan Sewerage District nearly $5 million.

In 2012, the U.S. Environmental Protection Agency determined the factory at 4132 N. Holton St. was "an imminent and substantial threat to public health and the environment." Two companies affiliated with past operators Pharmacia LLC and Fisher Controls International LLC agreed to pay for the cleanup.

As concrete slabs of old floors are lifted this month for disposal, the work is revealing previously undisclosed tunnels beneath the building housing sewer and water pipes, electric lines and hydraulic fluid lines and more PCBs, said Steve Mueller, a hydrogeologist with the state Department of Natural Resources' remediation and redevelopment program. An extensive tunnel network had been documented in company records dating from the building's construction in 1952 and completion of an addition in 1964.

Tunnels are six feet wide and 10 feet deep. Water and fluids that collected in the tunnels drained to an outdoor sump northeast of the building, toward the river. The sump drained to a sanitary sewer. Those connections were blocked in 2008, under an MMSD order.

Another unexpected discovery in demolition was that ceiling tiles absorbed so much PCBs over the years that many of the panels had to be separated from cleaner debris for disposal out of state as a hazardous waste, Mueller said.

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Demolition unearths legacy of toxic pollution at Milwaukee plant