On a chalky gray cliff along the Allegheny River just south of Ford City, the liquid runoff from a century-old glass waste dump has killed all the vegetation and formed icicles that are pink and yellow and rusty orange.

PPG Industries Inc.'s mountainous glass dump in Armstrong County, closed since 1970, is leaching toxic waterfalls and seeps that are contaminating the Allegheny River and underlying groundwater with high levels of lead, arsenic and manganese, according to University of Pittsburgh and Duquesne University researchers.

The state Department of Environmental Protection has a file dating back 30 years detailing the pollution, but the glass manufacturer is under no order to clean up the unhealthy conditions its dump is creating 38 miles upriver from Pittsburgh.

PPG's remediation efforts, negotiated over the years with the DEP and slowly implemented, have been ineffective, according to the department. PPG said last week it intends to work with the DEP to remediate the site.

The runoff reaching the river has pH levels of 12 -- higher than ammonia (11.5 pH) and just slightly lower than bleach (12.6 pH).

"The pH is outlandish," said Dr. Conrad Dan Volz, assistant professor in Pitt's Graduate School of Public Health. He is heading the water-quality research in the Allegheny River watershed.

"This is a prime recreational and fishing place for people in the area. We see people fishing off this bank," he said.

"At the very least there needs to be signs posted all along the riverside stating this water coming in here is immediately dangerous to life and health, because in essence if you tried to wash your face with it you could get caustic burns to your eyes. You could get skin burns."

Fish cannot live in water with a pH higher than 10.1, and a fishing survey conducted last summer by Pitt's Allegheny River Stewardship Project found no game fish near where the runoff enters the river. Fumes from the runoff sickened several university researchers in the summer.

Shallow wells that Dr. Volz's Pitt students dug along the river revealed dangerous levels of arsenic, lead, selenium, zinc and manganese in the sediment and underlying groundwater.

"There are problems here along the river that PPG should be looking into," Dr. Volz said. "The company does have a pump-and-treat system on the part of the dump that drains to Glade Run, an Allegheny tributary, but not on the part that drains directly into the river."

Commonly known as the "PPG glass dump," the 72-acre site was used until the late 1960s. PPG disposed of a host of metals, chemicals, broken glass and scrap products, volatile and semivolatile organic compounds and polychlorinated biphenyls (PCBs) in connection with manufacturing architectural glass at the world's largest plate-glass factory, in nearby Ford City.

Dr. Volz estimated that the disposal area on the property covers an area 100-yards-long, 50-yards-wide and is stacked with glass and other materials 25-yards-high. Souvenir hunters cut holes in the fence surrounding the dump to cart off bread-loaf-size chunks of cobalt-blue and green glass for yard ornaments.

PPG sold the property to Ford City for $1 in 1972, an ownership transfer that has complicated its cleanup, according to documents in the DEP's files. Ford City has maintained a community park with baseball fields on a section of the property along state Route 128 and away from the river, which is heavily used by pleasure boaters, canoeists and fisherman in the section of Pool 6 adjacent to the site.

"The reason we looked at this site is that people up here asked us to. They water ski, fish, and recreate on the river and they're concerned about it," Dr. Volz said. "They see this dead hill and they know something's wrong but they don't know the pH is 12."

The DEP, reacting to the Pitt research findings, conducted water sampling in early November and found pH levels of 12 -- indicating extremely high alkalinity -- at two of four sampling locations.

The term pH refers to the degree of acidity or alkalinity of a solution. It is measured on a zero to 14 scale -- a pH of 7 is neutral, lower pH is acidic and higher pH is alkaline. Normal ground water pH ranges from 6 to 8.5.

The 18-page DEP sampling report also shows high levels of arsenic, lead, manganese and aluminum in the water coming off the site and into the river. It notes that "Enforcement and meeting being planned with PPG to remediate site and control seeps entering into the Allegheny River."

Neither Ford City nor PPG has a permit to discharge those pollutants into the river from the site.

"We are concerned about the site and are considering what enforcement alternatives are available," said Helen Humphreys, a DEP spokeswoman. "We're holding PPG responsible as we have in the past and will continue to do."

She said PPG has been working with the department's environmental cleanup program and taken remedial action, but "as evidenced by the seepage it wasn't enough." The high pH of the site runoff is diluted and reduced when it enters the river, but Ms. Humphreys said that doesn't mean riverbank and aquatic life aren't being affected.

"The solution is for the site to be cleaned up," Ms. Humphreys said. "This is one of a number of sites in the Pittsburgh area that is a legacy of the region's industrial heritage. One of the reasons it's garnering attention now is that we've been successful doing other cleanups."

Jeremy Neuhart, a PPG spokesman, said the company has done "remedial site investigations and interim site stabilization" and submitted a "notice of intent to remediate" the seeps and runoff under the state Brownfields Program. The company has also met with the DEP and Ford City to "incorporate recreational use as a component of the remediation," he said.

"Representatives from PPG have met with the (Pitt) research team and are reviewing the study, its methodologies and results," said Mr. Neuhart, adding that the researchers didn't take into account remediation work PPG has already done.

But DEP records show PPG previously has argued that the high pH of the seeps is beneficial to the Allegheny River because it helps to neutralize acid drainage from abandoned mines, and the company has raised ownership of the site as an issue. At a meeting last month, Dr. Volz said PPG officials claimed the whole site is a park and said they want it treated as a former industrial site under the Brownfield program, which has less stringent cleanup requirements than nonindustrial sites.

"There's a bit of a game being played here," Dr. Volz said. "But now the DEP knows it can't just let this sit in its files anymore. It knows it can't allow this stuff to continue to discharge into the river."