A state investigation has found that Story City students and teachers face no schoolyard health threats from toxic chemicals emitted by a local plant.
A USA Today study using basic modeling in December predicted Roland-Story's elementary and high schools could face dangerous levels of a toxic chemical emitted by American Packaging Corp. Those schools were listed among the most-threatened in the country.
However, the newspaper's nationwide, school-by-school analysis did not factor in variables such as weather patterns, topography or local plants' stack heights.
A recently completed Iowa Department of Natural Resources modeling effort found levels of toxic chemicals from American Packaging would be "basically zero" around town, said Lori Hanson of the Iowa Department of Natural Resources' air-pollution modeling staff.
The predicted levels are far lower than the health limits suggested by the Iowa Department of Public Health.
The USA Today study found 224 of 1,785 Iowa schoolyards ranked in the top 10 percent nationally for toxic air at the sites, based on a federally approved computer model and data reported by some of the state's largest businesses.
Among Iowa schools near the top of the national rankings were Roland-Story's high school and elementary school; Cardinal Stritch Junior-Senior High School in Keokuk; Edison Elementary and Thomas Jefferson High in Council Bluffs; and Johnson Elementary in Cedar Rapids.
The USA Today study did not include emissions from vehicles, a major source of cancer-causing emissions in Iowa. Smaller facilities weren't included because they don't have to report to the federal inventory.
At Story City, the DNR worked with American Packaging Corp. to get stack emissions data, Hanson said. The state then used its own modeling system, which is more specific than the U.S. Environmental Protection Agency's screening system used by USA Today. The state model included stack heights and five years' worth of weather data.
Roland-Story Superintendent Mike Billings said local residents didn't panic over the possibility of toxic exposures. Nonetheless, they will welcome confirmation that American Packaging's emissions are not causing health issues in town. Billings praised the quick and thorough response of DNR and the health department.
USA Today's analysis had raised the prospect that the schoolyards at Roland-Story's high school and elementary buildings might have dangerous levels of diisocyanate - a chemical that can cause lung damage - emitted from American Packaging.
The state also modeled levels of five other toxic chemicals that could be a concern in industrial areas: hexane, formaldehyde, toluene, benzene and vinyl acetate. All were shown to be at safe levels in Story City, Hanson said.
A federal contractor later this month will install a monitor in Story City as part of the U.S. Environmental Protection Agency's two-month follow-up to USA Today's reports.
The state now will focus its modeling efforts on dozens of other Iowa school districts that appeared in the USA Today study, said Catharine Fitzsimmons, air-quality bureau chief. That work is expected to take months.