The regional Air Pollution Control District on Friday issued a health cautionary statement for San Joaquin, Stanislaus, Merced, Madera, Fresno and Tulare counties, especially for foothill and mountain areas.
Officials say the impacts from the 315-square-mile blaze will be felt throughout the Labor Day weekend.
Previously, the fire prompted unhealthy air alerts in Nevada.
Residents who see or smell smoke should stay inside, especially people with heart of lung problems, older adults and children.
The 2-week-old fire is now the largest to date this year in the U.S. It's 32 percent contained.