Cement factories have brought thousands of jobs and years of prosperity to Midlothian, Texas a thriving community of about 12,000. But environmentalists say the cement plants are also responsible for some of the worst pollution in the state as their high-temperature kilns pump out millions of pounds of toxic pollutants such as arsenic, cadmium, benzene and dioxins each year. "There’s no way we know what the effect will be of these thousands of chemicals on people’s health," said Jim Schermbeck, an environmental activist with a local group called Downwinders at Risk. "But what we do know is that some of these are chemicals that we’ve never been exposed to before."

City officials strongly deny that anything is amiss, citing more than two dozen state studies in the past 10 years that failed to find any correlation between pollution from the cement plants and adverse health effects. Local officials insist that toxic emissions from the cement plants remain within the limits set by the Texas Commission on Environmental Quality.

Only four studies by the Texas Department of State Health Services have examined suspected disease clusters and birth defects in and around Midlothian in the past decade. One found unusual levels of Down syndrome between 1992-94, but a later study found that Down syndrome was "not significantly elevated," and other types of cancer and diseases were found in the studies to be "within normal ranges."

"There have been a lot of allegations — people saying, ’I know of someone who has cancer,’ " said Dr. Richard Beauchamp, senior medical toxicologist at the state health agency in Austin. "A lot of people’s idea of a cancer cluster is if they know someone who has breast cancer and another person who has lung cancer and another who has brain cancer. But all the clusters we’ve looked at from the Midlothian area failed to have much statistical significance."

Schermbeck, however, faults those health studies because they were based on statistics and computer models rather than field research. Moreover, environmental groups allege the "acceptable" levels of pollution permitted by state authorities are set too high for the benefit of industry — a situation that they say led Ellis County, where Midlothian is located, to exceed federal Clean Air Act guidelines last year.