The toxin chromium 6, which was brought to widespread attention by the efforts of legal figure Erin Brockovich, may have been unwittingly produced by a Californian plant for a total of six years, it has emerged.
Abnormal levels of the substance were detected in the atmosphere outside the plant in February, but now the cause of this has been identified, according to Ed Kendig, executive director of the Monterey Bay Unified Air Pollution Control District.
Mr Kendig said the firm can prevent further incidences by ensuring the chromium 6-contaminated dust drift from the loading of cement trucks is regulated.
"They have to really tighten up on their plant procedures, tighten up on their fugitive dust. Fugitive dust has always been an issue there," he stated.
In March last year, researchers at Brown University in the US found that when even small doses of chromium 6 came into contact with vitamin C in human cells, it initiated DNA damage, which can in turn result in cancer.