The controversial head of the U.S. Environmental Protection Agency’s San Francisco headquarters was abruptly dismissed without explanation Wednesday after less than two years on the job.

Mike Stoker, a 63-year-old former Santa Barbara County attorney, had been widely criticized for trying to oversee more than 600 San Francisco employees from his home in Los Angeles. He had also come under investigation after a complaint was filed accusing him of excessive travel. Still, it wasn’t clear what led to his sudden departure.

“I would like to thank Mike Stoker for his service to EPA,” wrote EPA Administrator Andrew Wheeler in an internal memorandum obtained by The Chronicle. “I wish him and his family the best in their future endeavors.”

The memo said the new acting regional administrator would be Deborah Jordan, a 30-year EPA employee who has served as assistant regional administrator in San Francisco since 2016.

Stoker was in charge of the EPA’s Pacific Southwest Region, known as Region 9, covering California, Nevada, Arizona, Hawaii and the Pacific islands. There are 111 Superfund sites in Region 9, most of them in California.

The regional office is in San Francisco, where 93 percent of the 663 employees are stationed. Stoker, who lives in Carpinteria (Santa Barbara County), nevertheless petitioned to have his duty station changed to Los Angeles and that request was granted despite criticism from Sen. Dianne Feinstein and others.

He pointed out shortly after he was hired in May 2018 that Southern California is a huge area with at least as many environmental problems as the Bay Area.

“I don’t think it matters at all (where the administrator lives),” he said. “I’ll be on the road.”

Those familiar with his travel, including sources within the EPA, said he, in fact, spent huge amounts of time on the road, including trips to Hawaii and Guam.

In March 2019, the EPA’s Office of the Inspector General investigated a “hotline complaint” about how much time Stoker was spending away from San Francisco and “his excessive number of trips.”

The office issued a “Management Alert” that documented how he spent $43,875 in taxpayer funds on 35 separate trips between May 2018 and February 2019, including two trips to Hawaii, one to Japan and another to Saipan, in the Mariana Islands. The report, which did not reach any conclusions about the propriety of his travel, said he spent only 30 out of 145 workdays in San Francisco.

Before coming to the EPA, Stoker was a Santa Barbara County attorney and county supervisor who fought for farmers and the fossil fuel industry and led the “lock her up” chants in opposition to Hillary Clinton. He once worked at a fossil fuel company that was prosecuted by the EPA for a series of oil spills and has questioned the scientific consensus on climate change.

Stoker often talked about how he was an EPA ambassador who carried out Trump Administration directives, but did not get involved in policy decisions. Remediating and closing Superfund sites “is one of my top priorities,” Stoker told The Chronicle after his appointment.

Environmentalists and EPA managers, however, insisted that the policies of the EPA that Stoker followed were to cut staff, relax regulations at toxic sites and decrease critical oversight of polluting industries.

He had previously promoted Deborah Jordan from acting to permanent deputy regional administrator. Now she will take over his job.

Peter Fimrite is a San Francisco Chronicle staff writer. Email: pfimrite@sfchronicle.com. Twitter: @pfimrite