The EPA is managing the cleanup of the site of the former Milwaukee Die Casting plant. Water contaminated by PCBs used in process oils and fluids are still trapped in water pockets in utility tunnels that connected areas under the plant. Some soil also contaminated with PCBs also is being cleaned up. Credit: Michael Sears

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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.

Tunnels revealed

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.

Contaminated tiles

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.

Non-hazardous rubble is being trucked to the Emerald Park landfill in Muskego, said Kathy Halbur, the EPA's on-scene coordinator.

Hazardous waste — any material containing more than 50 parts per million — is shipped to a landfill in Belleville, Mich.

Water pumped from the tunnels and lower-level rooms is being treated to remove PCBs. Clean water is stored in blue tanks on site until a decision is made on where it will be disposed of, Halbur said.

Chemical sludge from the treatment process is being shipped to Port Arthur, Texas, for incineration. Wastewater pumped out of storm sewers last year was sent there, too.

Pharmacia and Fisher Controls have spent $4 million on the cleanup to date, according to Halbur.

The building was razed in late May. After remaining concrete slabs are removed, workers will begin excavating contaminated soil this fall, Halbur said.

Though parts production ceased in 1997, the first indication of the abandoned factory's health-threatening reach came to light a decade later when its PCBs were found in Milorganite sewage sludge fertilizer.

MMSD did not learn of the contamination before large piles of tainted fertilizer had been given away for use at Milwaukee County parks and Milwaukee Public Schools recreational areas. Thirty public recreational areas were closed in the summer of 2007 until top soil could be scraped off the fields, or tests showed contamination was low enough not to threaten public health.

$5 million contamination

After counting lost Milorganite sales, cleanup of the fertilizer factory and storage silos on Jones Island, and removal of tainted fertilizer from several of the recreational fields, the cost of that contamination added up to nearly $5 million, district officials said at the time.

A 2008 investigation revealed that the former Milwaukee Die Casting plant was the primary source of PCBs in the city sewer and a regional sewer it emptied into. Those chemicals contained in molasses-like hydraulic fluid accumulated in sediment at the bottom of the pipes.

A large quantity of PCBs remains in a large regional sewer — known as the central metropolitan interceptor sewer — that runs along the river downstream of Capitol Drive and the former Milwaukee Die Casting plant, according to MMSD officials. The interceptor sewer empties at Jones Island.

Six years after the district's investigation, the EPA's regional office in Chicago has not approved a cleanup plan for that sewer.

Use of PCBs was banned in 1979 after studies linked exposure to the chemicals to immune system damage and cancer.

DNR records show that the last owners of the plant, George and Theresa Slyman of Ohio, did not comply with court-ordered cleanups in 1997 and 1998. George Slyman died in 2009 and the property was abandoned.

The City of Milwaukee later acquired the site through foreclosure and transferred ownership to the city Redevelopment Authority.

After cleanup work is completed early next year, EPA restrictions will limit reuse of the property, said Karen Dettmer, senior environmental project engineer with the redevelopment authority. No high-density housing or office buildings will be allowed.

A parking lot is one option, or a low-density commercial development.

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