Factories, power plants and other sources in Virginia reported an 18.6 percent increase in toxic-chemical releases in 2006, a state report says. Reported releases to waterways nearly doubled.

The industries released 66.3 million pounds of toxic materials, up from 55.9 million pounds in 2005.

The substances, such as sulfuric acid, chlorine and mercury, are considered so potent that, in sufficient concentrations, they could kill or cause cancer, reproductive problems or other disorders in people, fish or wildlife.

The increases are detailed in a report the state Department of Environmental Quality released yesterday.

The latest numbers increased primarily because one company corrected estimates it previously had miscalculated.

The company, a division of Alliant Techsystems Inc., operates the federally owned Radford Army Ammunition Plant in Southwest Virginia. The company makes materials that propel rockets and mortar shells, as well as medium-caliber ammunition.

Company and Army officials said this is what happened:

The company reports wastewater discharges of nitrogen under a different state program, designed to protect waters. The toxic-release program, however, requires the disclosure of releases of nitrates, which are related to nitrogen but are released in greater volumes.

The company realized last year that it had not made the calculation required to estimate the larger figures accurately.

"Once we did discover it, we immediately self-disclosed it" to state and federal regulators, said the plant's commander, Lt. Col. Jon Drushal.

"Even though we found the mathematical error, there are no more nitrate compounds being released today than there were yesterday."

The company released about 13.5 million pounds of nitrates in 2006. For years, similar releases had been reported incorrectly at about 2.5 million pounds, company officials said.

High nitrates in drinking water can cause a potentially fatal blood disorder in infants, and it can harm fish in streams, experts say.

Drushal said the plant's releases complied with state and federal limits designed to protect people and the environment.

The revision helped raise Virginia's overall toxic releases to waterways 96.9 percent, to 19.5 million pounds.

"We hope this is an isolated case," said Kristen Hughes, a staff scientist for the Chesapeake Bay Foundation, an environmental group.

According to the new report, toxic chemicals released into the air totaled 42 million pounds, up 1.9 percent.

Chemicals buried or put on land totaled 4.9 million pounds, up 0.99 percent.

The effect of the releases on the public is not clear. Many of the chemicals become diluted in air and water, and state officials say they have no evidence of anyone being endangered.

But DEQ spokesman Bill Hayden said, "There is no absolute guarantee" that everyone is protected.

Emissions in the report are legal, but publicity about them has spurred many companies to get cleaner.

Virginia's toxic releases have fallen significantly from 151.2 million pounds in 1988, when the reports began.

Contact Rex Springston at (804) 649-6453 or rspringston@timesdispatch.com.