A cement factory near Riverside is emitting high levels of hexavalent chromium, a toxic carcinogen, from enormous outdoor dust piles blowing downwind across an industrial area and a residential community, the region's top air regulator told The Times on Monday.
Barry Wallerstein, chief executive of the South Coast Air Quality Management District, said months of sampling and lab work showed that so-called clinker dust piles at TXI Riverside Cement in the Rubidoux area near the Riverside-San Bernardino County line were the source of high levels of airborne hexavalent chromium detected at sites in the area, including a uniform factory directly across the street.
"We're not aware of any previous reports that a cement factory would have this level of hexavalent chromium-related risk, but the fact of the matter is we have sampled downwind of the facility, we've sampled upwind of the facility, we cross-checked and did backward calculations using air quality modeling, and it's our best professional opinion that this is coming from the Riverside cement plant," said Wallerstein.
"They have very large piles of cement material . . . and we believe that the dust from these piles is causing a downwind hexavalent chromium condition."
A company official said TXI had been talking with air quality officials about the readings, but maintained that the company's plant had not officially been identified as the source of the emissions.
"We're obviously just as concerned as the district is," said Frank Sheets, a spokesman for TXI Riverside Cement. "I think the key here is verification . . . They're making an assumption, we believe at this point in time, that we're the source of that high concentration, and we need to go through a verification process, to verify their findings."
Wallerstein said that under California's toxic hot-spots law, the facility's owners would be required to notify the public of the emissions and take steps to mitigate them. He added that AQMD attorneys had advised him that the agency was not required to notify the public of the readings until the source of emissions had been confirmed.
The district had been in contact with TXI about the readings for about a month, according to the company.
Long-term exposure to airborne hexavalent chromium, also known as chromium 6, has been repeatedly linked in studies to terminal nasal and lung cancer. Recent studies, including one by the National Toxicological Program last year, have linked it to cancer in every major organ of the body in laboratory animals that drank contaminated water.
