Kennecott Utah Copper is the nation's second biggest toxic producer, according to the latest national tally by the U.S. Environmental Protection Agency.

And the mining company's waste kept Utah in 6th place nationally for toxic chemical releases, even though releases to the air, land and water declined.

EPA Administrator Lisa P. Jackson called the data a powerful tool for protecting public health and the environment.

"Serving the public's right to know is the crucial first step in reducing toxic chemicals in the places where we live, work, and raise children," she said in releasing the most recent "Toxics Release Inventory."

The 2007 data includes reports from about 22,000 companies on 650 chemicals. Overall, releases were down about 5 percent from 2006.

The trend was the same in Utah, which reported overall release of 169,070,157 pounds in 2007. That's about 14 percent less than in 2006.

Kennecott spokesman Kyle Bennett had a simple explanation for his company's high ranking: The more the company mines and cleans up, the more waste it reports.

"It all comes down to us moving material," he said.

The company moves about 150,000 tons of copper ore each day. And, in each ton, there are about 2 ounces of lead and 5 ounces of zinc, which both figure prominently in the annual report.

In addition, Bennett said, whatever material the company moves as part of a cleanup also must be reported as a toxic chemical. Kennecott's Bingham Canyon facilities account for about 85 percent of all Utah releases.

Meanwhile, the company has spent more than $2.4 billion to clean up past contamination from mining and to modernize the facilities still in use. "We're doing a lot to try to make a difference as well," said Bennett.

Mike Zucker, an environmental scientist who manages the state's toxics release data, noted that the top ten chemicals released in Utah are all somehow related to mining, from the trace minerals associated with ore -- such as copper, lead, zinc, arsenic and barium.

US Magnesium, which transforms Great Salt Lake minerals into alloys used to strengthen metals, reported releasing 4,335.93 grams -- or about 9.6 pounds -- of dioxins, the latest report said. That's about the same as in each of the past two years.

"There's nothing this year that's out of the ordinary," said Zucker.

The annual inventory, part of the "Community Right to Know Act," continues to be controversial, especially among mining companies that have topped the list since mining waste was added to the list.

But most agree it's gone a long way to raise awareness about the effect industrial activities have on the environment even though regulators don't use the data to regulate or restrict companies, only to track trends.

"It's an incentive to release less," said Zucker, noting that companies such as US Magnesium have voluntarily made dramatic reductions. "They're going to be driven by public opinion to a certain extent."

Back when the reports began in 1988, Utah releases of the so-called "1988 core chemicals" were about 121,990,439 pounds a year. Releases in 2007 were 28,242,035, less than one-quarter as much as that first year.

fahys@sltrib.com