In San Francisco's Mission District, a Shell station remains out of service while its steel tanks are replaced - a process that can be complex and hazardous.
During one removal, gasoline vapors inside a tank caused an explosion, underscoring the risks involved.
California first addressed the issue in 1984, when gas stations were barred from installing new single-walled tanks. The concern was environmental safety.
"We just don't want any foreign substance in our water supply," said Mark DeMarco of the Santa Clara Valley Water District during an interview with ABC7 news in the mid 1990s.
Back then, the state found that aging tanks were leaking MTBE, an additive used in gasoline.
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"MTBE is a potentially cancer-causing chemical in our gasoline that supposed to clean the air..." said I-Team reporter Dan Noyes, whose reporting uncovered contamination of drinking water.
In 2014, California ordered all single-walled steel tanks removed and replaced with double-walled fiberglass tanks. The change aimed to prevent leaks that can contaminate soil and groundwater.
"A lot of sites will impact ground water. Every single clean up case that I worked on, it does impact ground water," said Steve McMasters of the California State Water Resources Control Board.
During tank removal, environmental consultants such as David Grunat of Path Forward Partners, collect and analyze samples from surrounding soil and groundwater.
"We get brought in during the removal process," Grunat said. Testing can reveal a range of contaminants.
"Benzine, toluene, ethyl benzene, xylene, MTBE and TBA are other additives. If it's an old tank and very historical, we might be also looking for lead," he said.
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Cleanup efforts have come at a cost to consumers and the state. A fee of 2 cents per gallon of gasoline helps fund remediation of leaking tanks. According to the State Water Resources Control Board, California had about 50,000 single-walled tanks in the 1980s. Today, only 82 remain. The deadline to replace them or face closure and fines was Dec. 31, 2025. Nationally, many tanks are still aging. The Environmental Protection Agency reports that 40% of operating underground storage tanks in the United States are more than 30 years old, increasing the risk of leaks.
"In fact, some states were still allowing those to be installed in 2018-2019, that's single-walled tanks installed that late. We stopped in 84," said Tom Henderson of the California State Water Resources Control Board.
For gas station owners, compliance has been costly and time-consuming.
Michael Gharib of Twin Peaks Auto Care in San Francisco spent more than six months replacing his tanks after fighting to keep his business on city-owned land.
"Anything easy? Is there anything easy in San Francisco?" he said.
During the closure, revenue stopped while expenses continued.
"I carried my overhead. My staff stayed on the payroll. Yes, that was expensive. So far we've spent just about two million dollars," he said.
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The costs stem from permitting, construction and the installation of new tanks, along with lost business time. While the state offers loans and grants, some owners have opted to shut down rather than pay for upgrades. One example is the closure of the only gas station on Bay Farm Island in Alameda. Industry representatives say compliance remains a priority.
"We want to make sure that we are following all the rules. We want to be part of an outstanding community both in our environment and any of the environmental laws," said Elizabeth Graham, CEO of the California Fuels and Convenience Alliance.
Despite the challenges, some owners say the investment is worthwhile.
"And it's all because of Twin Peaks, the area, my community, I live here, I work here," Gharib said.
Experts say the new tanks provide critical environmental protection.
"Certainly, going to a double wall tank is going to provide a lot of protection for these communities where these underground storage tanks are located," Grunat said.
As California nears full compliance, the transition highlights the environmental benefits - and economic strain - tied to modernizing the state's fuel infrastructure.