For much of the 20th century the Ashley River waterfront in Charleston's Neck Area was crowded with factories that fouled the environment while producing fertilizer and treating lumber.

Arsenic and lead contaminated the soil where fertilizer was produced because the manufacturing process involved storing sulfuric acid in lead-lined tanks. Creosote and dioxin from treating wood crept into the groundwater, the marsh, and the high ground. Methane and pesticides leaked from an old county landfill.

The toxic chemicals rendered the land unfit for habitation, and even for industrial use, environmental regulators would later conclude.

The problems were little known or understood during the middle of the century, but by the 1990s many sites along the river had made the U.S. Environmental Protection Agency's national list of toxic properties and one was a Superfund site - a national top priority cleanup.

Now, through a series of multimillion-dollar projects mostly conducted during and after the recent recession at private companies' expense, many of those polluted sites have been cleaned up for industrial reuse. Hundreds of tons of contaminated soil and sediment were removed, and groundwater was treated.

"If you go down that river there's probably been $100 million of cleanup," said Craig Zeller, project manager at the U.S. Environmental Protection Agency, who was initially in charge of all of the Ashley River cleanup sites. "It was a huge success story for us."

It's a story that's still being told, however.

"It's everything from sites that have been totally cleaned up to sites that haven't been cleaned up, like Columbia Nitrogen," said Kenneth Seeger, president of community development and land management at MeadWestvaco, which holds the note on several large tracts eyed for redevelopment.

The former Koppers wood treatment plant site, on the south side of Milford Street, is still a Superfund site with an ongoing cleanup project.

"While the bulk of it was done, we continue to collect creosote there," Zeller said.

And cleanup work hasn't started on the adjacent Columbia Nitrogen site, where a fertilizer factory was once located, on the north side of Milford Street.

Exploding shrimp

Those sites are in the heart of the area where a plan to develop thousands of homes, hotel rooms and shops was announced a decade ago, known as the Magnolia development. A North Carolina company specializing in redeveloping industrial land planned to clean the land up to residential standards, but that plan faded away when the recession hit.

"When the economy tanked, they basically said they had changed their mind," said Ken Mallary, an EPA site manager for several of the projects.

The company, Cherokee Investment Partners, did not return calls seeking comment.

Without the extra funding to bring properties up to residential standards, most of the fertilizer plant sites were cleaned up to industrial standards, in keeping with their historic use.

Residential standards are stricter, to address concerns such as children who might play in, and ingest, soil contaminated with lead.

The happy ending to the environmental success story that regulators, city officials, community residents and real estate interests hope to see is the day when all the properties are cleaned up and redeveloped.

"It's a cliché, but we're trying to take these old lemons and make lemonade," Zeller said.

Those familiar with Charleston lore might suspect the EPA took notice of the Ashley River waterfront after the problem with spontaneously combusting shrimp in 1992. That's when a man who had been shrimping along the river was driving home across the old Cooper River bridge and noticed smoke coming from his cooler.

The reason? The shrimp had been exposed to phosphorous in the muck along the riverbed, near a chemical plant, and phosphorous spontaneously can catch fire when exposed to oxygen.

"Green groundwater"

Zeller confirms the shrimp incident happened, but Neck Area pollution first caught the EPA's attention when a company digging a barge canal along the Ashley River in the early 1990s hit a large waste pit created by the former Koppers Co.

"That released a bunch of creosote, there was a fish kill, and Koppers became a Superfund site," said Zeller.

Creosote, derived from coal tar, is a commercial wood preservative and pesticide that was used on telephone poles and railroads ties. A possible carcinogen, creosote is oily and flammable, and contact can irritate skin, eyes and lungs.

"We started looking to the south, and the north, and that's when these other sites were discovered," Zeller said.

Most of the Ashley River sites were once home to manufacturers of agricultural fertilizer; Swift Agri-Chem, Wando Phosphate, Stono Phosphate, Atlantic Phosphate Works, Columbia Nitrogen, and Ashepoo Phosphate and Fertilizer.

There was also a former Charleston County landfill, and on the Cooper River side of the Neck Area, and the Macalloy Corp. ferrochromium alloy smelting plant.

"They had Gatorade-green groundwater over there," Zeller said of the Macalloy site. "It was an interesting cleanup."

That cleanup involved digging about 1,000 cubic yards of contaminated sediment from the Shipyard Creek, and chemically modifying material contaminated with hexavalent chromium, which is known to cause cancer. Macalloy was one of the first cleanups completed in the Neck Area, and the property has been returned to use as an industrial site.

When the EPA oversees an industrial cleanup, it looks to the companies that caused the problems, or to the companies that merged with or otherwise absorbed the earlier companies. That's why ExxonMobil, as corporate successor to Virginia-Carolina Chemical Co., paid to clean up several of the fertilizer sites along the Ashley River.

In the 20 years since Koppers was named a Superfund site - placed on the National Priorites List of "the most serious uncontrolled or abandoned hazardous waste sites" in the nation - a quiet transformation has been taking place.

Along the Ashley River, in parts of both Charleston and North Charleston, five EPA-approved environmental cleanups have been completed, another is ongoing, and the seventh is scheduled for work this year.

However, all of the sites where work was completed would need additional cleanup if the properties were to be used for residential construction.

"EPA is not in the real estate business," Mallary said. "We just want to see the properties cleaned up, but they have to be cleaned to the expected future land use."

Most of the waterfront properties aren't much to look at now - mostly bare land covered with weeds and rubble. The Columbia Nitrogen cleanup should begin later this year, and then the big question for the future of the Neck Area will be what decisions are made about redevelopment.

Reach David Slade at 937-5552