The more things change, the more they stay the same. So it seems with regard to Erin Brokovich’s exposure PG&E’s contamination of Hinkley, California’s drinking water with the cancer-causing chromium 6.

The movie’s old news, but a plume contaminating groundwater with the probable carcinogen is currently expanding, forcing PG&E to offer to buy residents’ homes.

And it turns out that chromium 6 (also known as hexavalent chromium) was found in 31 U.S. cities‘ water supplies in a sampling of 35 cities. Among them, and in order of the severity of the contamination, are Riverside, San Jose, and Sacramento, California.

California has proposed a safe level of of .06 parts per billion, a limit that 25 of the city water supplies — including all of those in California — exceeded.

Industrial use of chromium 6 has dwindled since the Erin Brokovich’s time, and, as a strange footnote that shows how difficult it is to conclusively tie a contaminant with specific health effects, later studies have suggested that there is no cancer cluster in Hinkley.

Even so, I’m certainly going to stay tuned to see if the next round of tests includes San Francisco.