<p>Gas prices in California are soaring a week after a fire damaged the Chevron refinery in Richmond, a critical piece of the state's supply chain.</p>
<p>Prices at the pump jumped 25.8 cents in the Sacramento area over the past week, to $4 a gallon, according to market tracker GasBuddy.com. In San Francisco, motorists are paying $4.17 a gallon, according to a separate survey by AAA.</p>
<p>And it may be only the beginning.</p>
<p>"You probably won't see a break until mid- to late September," said Patrick DeHaan, senior petroleum analyst for GasBuddy.</p>