WASHINGTON — Utah's U.S. Magnesium has vastly reduced its chlorine emissions in recent years, but an environmental group said Wednesday that it is still the nation's worst polluter of "suspected neurotoxicants" and "suspected respiratory toxicants."

The U.S. Public Research Interest Group (PIRG) also said Tooele County, home of U.S. Magnesium's plant at Rowley, west of the Great Salt Lake, has the most such pollutants of any single county in America.

The environmental advocacy group used data from the Environmental Protection Agency's Toxic Release Inventory, which tracks release of pollutants by plant and location.

It then reorganized the data to develop lists of worst polluters in different categories, such as those releasing cancer-causing chemicals, developmental and reproductive toxicants or dioxin.

U.S. Magnesium's heavy emissions of chlorine made it No. 1 on two different lists — for "suspected neurological toxicants" and for "suspected respiratory toxicants." It included chemicals on those lists that it says government or academic researchers suspect may cause neurological or respiratory damage, including chlorine.

It also put Tooele County as the No. 1 most polluted county in America in those categories, and Rowley's 84074 ZIP code as those list's most polluted ZIP code nationally.

PIRG's study noted that U.S. Magnesium's chlorine emissions in Utah have been decreasing, and they "declined steadily from a 1989 peak of 110 million pounds to a 2000 level of 42 million pounds."

However, it said, "Magnesium Corporation's releases were still large enough to help make its Rowley zip code first in the nation for suspected neurotoxicant releases in 2000," as it also did for suspected respiratory toxicants.

The study said the Rowley ZIP code had 939.7 million tons of such releases between 1987 and 2000 — also the worst in the nation for that 14-year time frame, and more than twice as much as the next-worst zip codes in the two categories.

Rowley's ZIP code also ranked fifth worst in the nation in 2000 for release of dioxin, chemicals that may cause cancer.

U.S. Magnesium did not respond to Deseret News requests for comment before press deadlines.

In other categories, the study said Utah ranked 36th worst among the 50 states in release of cancer-causing chemicals with 306,397 pounds in 2000; 35th worst in release of developmental toxicants with 296,538 pounds; and 22nd worst in release of reproductive toxicants.

Despite high chlorine releases from U.S. Magnesium, Utah as a state ranked only 17th from the bottom in suspected respiratory toxicant releases — but eighth worst for suspected neurological toxicants, and fifth worst for dioxin releases.

While Tooele County was the worst county in the nation for suspected neurological and respiratory toxicants, Salt Lake County also made one "worst 50" list: finishing 50th worst in the nation for release of reproductive toxicants.

E-mail: lee@desnews.com