NDCA

Air study results are inconclusive

By SCOTT STREATER

Star-Telegram Staff Writer

Mon, Dec. 10, 2007

A long-awaited study of air pollution in Midlothian found levels of potentially dangerous benzene, arsenic, lead and other toxic chemicals at levels that exceed the most conservative health screening limits and “could be interpreted as posing a public health hazard.”

But state and federal health officials nonetheless concluded that more study is needed before saying “the extent of the public health hazard posed by air contaminants in Midlothian,” according to the report, obtained by the Star-Telegram.

The health consultation, which is set to be released Tuesday, found huge gaps in air monitoring and health-screening data and recommended that the state collect more air samples and research toxicology literature to further assess potential health risks. The draft report will be open for public comment beginning Tuesday, before final recommendations are made.

“We found that the majority of the risks associated with exposure to the chemicals analyzed in this health consultation were low,” according to the 128-page report. “However, we are classifying this site as an Indeterminate Public Health Hazard because further information is needed.”

The study was at the request of Midlothian residents, some of whom were disappointed by the vague findings.

The report does not name the individual sources responsible for pollution, nor does it guarantee recommendations will be followed. Its vague conclusions are likely to fan debate over whether state regulators need to crack down on industrial polluters in Ellis County, southeast of Fort Worth.

“I don’t know that we’ll ever have all of the answers,” said Midlothian Mayor Boyce Whatley, who had not seen the study late Sunday. “I would hope that the studies, if they are ever conclusive, show there are no long-term health effects because of the industrial emissions out here. But as a mayor and as a resident, certainly I want as much information as possible, and if there are additional studies that have to be done, I would favor those.”

So does Sal Mier and his wife, Grace, who spearheaded a petition signed by 371 residents that prompted federal health officials in July 2005 to study pollution in the city.

Mier, who until retiring in 1994 managed the Centers for Disease Control and Prevention’s five-state regional office in Dallas, said he just wants answers, and was disappointed. He has lined up a group of national and regional scientists to review the study and ensure that researchers used the latest peer-reviewed methodology.

“It’s not that we’re pushing for a negative outcome, but in arriving at this decision we’re not sure the most current science was factored in,” he said.

MIDLOTHIAN HEALTH ASSESSMENT

The study

The federal Agency for Toxic Substances and Disease Registry and the Texas Department of State Health Services agreed in 2005 to investigate whether air pollution in Midlothian is making people there sick. The study was undertaken after 371 Midlothian residents petitioned the federal agency to investigate the issue. The Agency for Toxic Substances and Disease Registry has no regulatory power and can only make recommendations.

Data gaps

A key component of the report is that it highlights gaps in data on a number of industrial pollutants, such as dioxins — a group of chemical compounds known to cause cancer. Because the state does not routinely collect air data for dioxins, and the consultation is based mostly on historical air sampling from state air monitors, the researchers could not address the issue even though it was one of the main concerns of the petitioners. They also could not evaluate asthma, immune system deficiencies and other health problems for the same reason. What’s more, researchers reported there are no health-based screening levels for 87 of the 113 contaminants the researchers measured. “Additional information is needed to determine the public health significance of these contaminants,” they reported.

Why it’s important

The study is expected to prompt additional research and will likely renew debate over whether regulation of Ellis County industrial polluters should be stepped up. Midlothian’s three cement plants — Holcim, Ash Grove and TXI Operations — and Chaparral Steel are among the largest industrial polluters in North Texas.

Contaminants of concern

These are some of the chemicals measured at high levels in the air in Midlothian:

Arsenic: No longer produced in the U.S., it has been used as a wood preservative and in pesticides; it is a known human carcinogen.

Lead: A metal, it is linked to behavioral and developmental disorders, and it can damage the lungs and kidney in adults and children. It is listed as a possible carcinogen.

Benzene: A highly flammable liquid used primarily to make other chemicals that are used to make products such as Styrofoam, dyes, detergents, drugs and pesticides.

1,2-Dichloroethane: A synthetic liquid most commonly used to make vinyl chloride, it is listed by the federal government as a probable human carcinogen.

For more information

The study is scheduled to be available Tuesday on the Texas Department of State Health Services Web site, www.dshs.state.tx.us/epitox/midlothian/midlothian.shtml

SCOTT STREATER, 817-390-7657
sstreater@star-telegram.com

http://www.star-telegram.com/news/story/350738.html