The local health director says a sixth birth-defect case has been confirmed in Kettleman City, where residents are battling plans to expand California's largest hazardous-waste landfill.

Keith Winkler says the county had not released information about the case because officials felt the state would eventually investigate and more cases could be revealed.

Health officials had reported that five of 63 children born between September 2007 and November 2008 suffered facial defects, and three of those children later died.

Last week, Gov. Arnold Schwarzenegger ordered two state agencies to investigate.

And on Wednesday, Jared Blumenfeld, administrator for the EPA's Pacific Southwest region, plans to visit Kettleman City and talk with residents.