Hundreds of current and former St. Louis Park residents claim they’re part of a cancer cluster, pinning the blame on decades of chemical contamination in the city’s historic industrial district.

The area near Hwy. 7 and Louisiana Avenue S. already hosts one of the nation’s first Superfund cleanup sites, a long-shuttered creosote plant that treated railroad ties and telephone poles for more than 50 years. Reilly Tar and Chemical Corp. closed in 1972, and the area since then has been closely monitored by federal, state and city agencies.

Now the city is dealing with a second chemical plume, from other industries in the same area, that has spread through deep groundwater far into neighboring Edina.

Public health officials say there’s virtually no chance that the environmental pollution in St. Louis Park has affected the city’s cancer rates. Even so, levels of toxic chemicals in some areas near the plume’s source have measured hundreds of times greater — in some cases, thousands — than federal safety standards allow.

Investigators tested more than 200 air, water and soil samples near the plume’s source. They found hundreds of instances of chemicals exceeding allowable limits, including tetrachloroethylene, naphthalene and vinyl chloride.

The U.S. Environmental Protection Agency confirmed that it is working with state officials to assess the chemical plume as a potential Superfund site. If designated, it would be only the fourth Minnesota site added to the Superfund list since the 1980s.

The ongoing water contamination crisis in Flint, Mich., has only added to the concerns of some St. Louis Park residents, past and present.

“You look at Flint and see how long they lied to people,” said Nancy Williams, a Shoreview resident who grew up six blocks from the Reilly plant. “You don’t know who you can trust anymore.”

St. Louis Park officials say they welcome the scrutiny and are eager to share information on cleanup efforts. They believe they’ve done everything possible to deal with a legacy of pollution created long before they were in office.

“Protecting the city’s drinking water supply is our most serious responsibility as city officials,” said City Manager Tom Harmening. “For our utility staff, it’s part of their everyday work to follow all of the rules and regulations to ensure our drinking water is safe, including the extra measures required due to the missteps of some past industry in the city. While it’s never a routine responsibility or one taken lightly by our staff, it is a responsibility we’ve been living with for a long time.

“We appreciate that the recent actions of interested citizens have drawn our attention to the need to continue to talk to our residents about the extraordinary and careful measures we take, in partnership with other government agencies, to ensure the health and safety of our drinking water supply. The city of St. Louis Park’s drinking water is safe, thanks to the efforts of our dedicated staff and partner agencies.”

Meanwhile, state officials say that the odds of anyone getting cancer from living near the contaminated sites are practically nonexistent.

“These are very vexing issues. I’m not surprised at all that you have a group of people with these beliefs,” said Alan Bender, chief of the chronic disease and environmental epidemiology section at the Minnesota Department of Health.

However, he said, “there’s virtually zero possibility that these low-level contaminants have increased the cancer probability in the community.”

Bender noted that tobacco use, diet and obesity, and heredity account for more than two-thirds of cancer cases. In fact, every adult Minnesotan has a 50 percent chance of developing a life-threatening malignancy, he said. As better treatments are found for diseases that used to be death sentences, people live longer and face a higher risk of cancer as they age.

“The last thing people should worry about is the impact of man-made pollution, and it’s often the first thing,” Bender said. He added that he’s puzzled by the “disconnect” between what science shows and what people believe.

Intense interest on Facebook

Try telling that to the nearly 1,300 members of the St. Louis Park cancer cluster group on Facebook.

Some are simply looking for information. But many are convinced that they — along with family members, friends and neighbors — face health issues from growing up near the Reilly plant when it produced track ties for four railroads and supplied most of the pilings for Minnesota highway bridges.

Marilyn Schultz, of Santa Cruz, Calif., was born in St. Louis Park in 1951 and lived there until she graduated from high school. Her parents, she said, used their private well long after many other homes had switched to city water. Both died of colon cancer in their 60s, and two of her four sisters have had cancer.

“All these years I’ve thought of the possibility that the water could have affected them, and could have affected us,” she said.

Barb Waller of Blaine started the Facebook cancer group last fall. A resident of St. Louis Park from 1960 to 1980, her mother died of leukemia and three other family members have suffered from neurological disorders. She “absolutely” believes that the Reilly site contributed to her family’s health problems.

“I remember climbing on the wood that was drying and thinking, ‘What is this gooey stuff?’ ” she said.

On the Facebook site, Waller marks the address of every case of cancer or neurological disease reported by group members. She places a skull and crossbones on every place reported as contaminated by government agencies.

So far, her map has more than 800 markers, she said, “and I figure I’m missing at least 1,500 or 2,000 pins.”

Officials: Water is safe

The second chemical plume has been known about for at least 15 years, but only recently did public officials discover its source: a collection of five businesses including a dry cleaner, a printing company and a firm that made radiator coils. The businesses used cleaning solvents and degreasers that leaked into the soil and down to the water table.

Unlike the Reilly pollution, which is heavy and fairly stable, the groundwater plume is made up of volatile organic compounds, or VOCs. They spread easily and multiply as they break down into their chemical components.

But VOCs also can be efficiently removed from water, according to public works officials in St. Louis Park and Edina. Officials in both cities firmly maintain that their drinking water is safe.

“It’s good, clean, safe to drink,” said Mark Hanson, public works superintendent in St. Louis Park. He noted that water quality in the city is strictly monitored by the EPA, Minnesota Pollution Control Agency and state Health Department, in addition to the city’s own regular testing.

St. Louis Park uses a variety of methods to ensure that chemicals are removed from its water, including two giant filtration units that each contain 20,000 pounds of granular activated carbon.

While the city’s water has tested within safe limits, the chemical plume has recently caused test results to “bump up against” allowable limits for VOCs, Hanson said. The city is working with federal and state regulators to test some additional methods of removing the VOCs.

Edina pumped more than 2.3 billion gallons of water from its municipal wells last year, and every gallon passed quality standards, said Brian Olson, the city’s public works director. In 2012, the city opened a new treatment plant specifically designed to treat water affected by the chemical plume. It uses a method called air stripping, in which air is injected into the water to help dissipate the VOCs.

“First and foremost, we are confident that the city of Edina water is safe,” Olson said.

Study: No spike in cancer

In March, the state Health Department released a 20-year study of cancer rates in St. Louis Park. Looking at the period from 1993 to 2012, the researchers concluded that “overall cancer incidence and mortality rates in St. Louis Park are virtually identical to cancer rates in the Twin Cities metro area.” Based on established probabilities, the study expected to find 5,499 new cases of cancer among city residents and found only a slightly higher number — 5,523.

Members of the Facebook group say that the study didn’t include residents who grew up in St. Louis Park and later moved elsewhere. Bender said the study also would include residents who may have had exposure before moving to St. Louis Park, making it a wash.

“The measure of the appropriate response is people living in that community,” he said.

If anyone had reason to be concerned about cancer from soil and water pollution, it might be Gregg Lindberg, the City Council member who represents the area where the Reilly plant was located. Lindberg’s father, Dennis, worked as an accountant at the Reilly plant for 10 years and died in 2010 of a rare form of thyroid cancer at age 67.

Lindberg said members of his father’s Mayo Clinic treatment team unanimously agreed that his cancer was most likely the result of genetics and had nothing to do with exposure while working at Reilly.

“I have a lot of sympathy and empathy for folks who are dealing with the disease themselves, and have family members who are going through the same things my dad did,” Lindberg said.

He said the city will do everything it can to make pollution information available to residents.

“If there’s one thing I’ve learned throughout this process, it’s that open, honest dialogue and access to information is critical to making sure the public feels safe and secure at home,” Lindberg said. “People will fill in the blanks. If there is information missing, or they don’t understand, the natural reaction is to be afraid or concerned.”