Because there is always a short end of the cap-and-trade stick, the concern about concentrating emissions is not theoretical:

Michael Toth, who lives less than a mile downwind from the Clawiter Road site where Tierra wants to build the plant, said the credit exchange means his neighborhood will bear an unfair level of pollution.

Help Grist raise $25,000 by September 30 to further advance our climate reporting

"The purchase of credit essentially allows a company to move pollution from one part of the Bay Area to another," Toth said. "I don’t think the laws in this state have recognized the problems that can be created as an abuse of the credit system."

Gerard Clum, president of Life Chiropractic College West, located directly across the railroad tracks from the site, is also skeptical.

Grist thanks its sponsors. Become one.

"I think the biggest thing from where I sit is with the particulate matter discharge," Clum said. "(Credits) are fine for the region, but it doesn’t do much for Hayward."

The man’s got a point.