HINKLEY, Calif. – Ten days before Christmas 1965, Pacific Gas & Electric Co. station chief Richard Jacobs walked a half-block on a dusty road lined with scraggly creosote shrubs to check out a neighbor’s toilet.

Jacobs carried with him a secret, something he referred to as the “chromate problem.”

Starting in 1952, the power company began mixing a toxic form of chromium with water to prevent rust at a new pipeline pumping station in Hinkley, a remote desert community united by a single school and a general store. PG&E dumped the chromium-laced water into a pond.

Lately there had been reports of problems with the neighbors’ wells. PG&E had just drawn greenish water from one well and discovered high levels of chromium. Now, retired farmer John Speth was complaining of greenish deposits in his toilet bowl.

Jacobs took a look in the bowl but assured Speth that PG&E had nothing to do with it. “When I left Mr. Speth,” Jacobs later wrote in longhand, “he was satisfied but still concerned about his water.” Speth died of stomach cancer in 1974.

It wasn’t until Dec. 7, 1987 — 22 years after that visit to Speth’s house — that PG&E finally told the local water board that it had contaminated the underground water. The company claimed it had discovered the problem just one week earlier.

From here, the story is familiar to anyone who saw the hit film Erin Brockovich. The corporate polluter was taken to court. The victims got millions of dollars. Problem solved.

In September 2010, scientists at the Environmental Protection Agency came to a startling conclusion: Even a small amount of a chemical compound commonly found in tap water may cause cancer.

The compound, hexavalent chromium, gained infamy in the Oscar-winning film Erin Brockovich, based on the David-vs.-Goliath legal duel between desert dwellers in Hinkley, Calif., and Pacific Gas & Electric Co. The film ends in Hollywood fashion, with the corporate polluter paying $333 million to people suffering from illnesses.

But in real life, the drama continues. More than 70 million Americans drink traces of chromium every day, according to the Environmental Working Group, a nonprofit research organization.

And now, more than a decade after the film, EPA scientists cite “clear evidence” that the chemical compound, also known as chromium (VI), can cause cancer. The federal agency was poised to announce its findings in 2011, a step almost certain to trigger stricter drinking-water standards to prevent new cancers and deaths.

The chemical industry’s trade association and chief lobbyist, the American Chemistry Council, urged the EPA to wait for more research, a common practice to delay action on toxic chemicals. However, Vincent Cogliano, the soft-spoken head of EPA’s chemical-assessment program, rebuffed the powerful group, writing in an April 2011 letter that “strong” new research was already available.

In 2007, when Deborah Rice was appointed chair of an Environmental Protection Agency panel assessing the safety levels of flame retardants, she arrived as a respected Maine toxicologist with no ties to industry.

Yet the EPA removed Rice from the panel after an intense push by the American Chemistry Council (ACC), an industry lobbying group that accused her of bias. Her supposed conflict of interest? She had publicly raised questions about the safety of a flame retardant under EPA review.

Rice’s travails through the EPA’s Integrated Risk Information System, or IRIS, program reveal the flip side of industry’s sway. Not only does the ACC back many scientists named to IRIS panels, it also has the power to help remove ones it doesn’t favor.

The ruckus over the Maine scientist surfaced six years ago, but its lesson echoes today.

To Rice, her removal points up an irony borne out by a Center for Public Integrity investigation: Scientists with deep ties to industry are allowed to continue on IRIS panels. But she — with no financial link to industry — was booted.

“It wasn’t like I was a consultant, saying this stuff is really bad because someone is paying me to do it. I was the toxicologist working for the state of Maine asked by my department to do these reviews,” she said. “That was the basis on which they said I was in conflict.”

Another irony: Rice’s assessment was on target. Two years later, the EPA moved to cease production of decaBDE, a chemical it views as a possible carcinogen. In Maine, Rice’s research had supported a state ban on the chemical.

The Environmental Protection Agency’s inspector general has begun a review of the EPA’s use of internal watch lists to target enforcement of federal pollution laws. The watch lists first came to light as part of a 2011 investigation by The Center for Public Integrity and NPR.

The inspector general is exploring “potential improvements in the protection of human health and the environment by ensuring the EPA is enforcing environmental laws and cleaning up communities,” the IG’s office wrote last month to Cynthia Giles, the EPA’s assistant administrator for the Office of Enforcement and Compliance Assurance.

The watch lists include allegedly chronic violators of the Clean Air Act, the Clean Water Act and the Resource Conservation and Recovery Act, which governs the handling of hazardous waste.

The EPA began to post the previously secret lists online in the fall of 2011 in response to a Freedom of Information Act request filed by the Center as part of the “Poisoned Places” investigation.

The project revealed that – two decades after Congress sought to crack down on chemicals that can cause cancer, brain damage and other ailments – toxic air pollutants continued to plague parts of the United States. The reports found that there were some 1,600 “high priority violators” of the Clean Air Act – nearly 400 of which were on the EPA’s watch list – and that federal and state regulators sometimes had trouble keeping tabs on oil refineries, power plants, steel mills and other industrial facilities that showered communities with contaminants.

DETROIT — In an economically distressed pocket of southwest Detroit known by its ZIP code — 48217 — the weekend of September 7-9 was one of the worst, pollution-wise, residents like Theresa Shaw could remember.

“I started smelling it on Thursday,” said Shaw, who immediately suspected the Marathon Petroleum Co. refinery a half-mile from her house. “I kept the windows closed because I couldn’t breathe. On Friday, I thought, ‘What the heck are they doing?’ My eyes were just burning, my throat was hurting, my stomach was hurting. I was having migraine headaches.

“The smell, it was like this burning tar, with that benzene and that sulfur. I wanted to scream.”

Shaw retreated to her sister’s house on the north side of town. Responding to citizen complaints, the Michigan Department of Environmental Quality traced the powerful odor to Marathon, which had been cleaning several large vessels, and wrote up the company for a nuisance violation.

Marathon says it is “committed to environmental responsibility” and acted quickly to correct the odor problem, a byproduct of plant maintenance.

Yet the episode further eroded residents’ trust in the company and underscored their fears about a $2.2 billion refinery expansion that will allow Marathon to process more high-sulfur Canadian crude oil.

The build-out, nearly complete, won’t add to the air pollution burden, Marathon promises. In fact, the Ohio-based company vows, emissions of some pollutants will go down and job numbers will go up.

Shaw doesn’t buy it. “They’ve disrespected us in this neighborhood over and over and over again,” she said.

Fifteen residents of Corpus Christi, Texas — so sickened by pollution they have been deemed crime victims — are asking a federal judge to force Citgo Petroleum Corp. to set up multimillion-dollar trust funds to cover medical and relocation costs, in a case with national ramifications.

A jury in 2007 convicted Citgo of criminal violations of the Clean Air Act, concluding that the company’s Corpus Christi refinery allowed toxic chemicals to drift from two large, uncovered storage tanks into a nearby neighborhood for a decade.

The company was to have been sentenced last month; the Department of Justice has proposed a fine of slightly more than $2 million. Lawyers for the 15 residents, however, asked U.S. District Judge John D. Rainey to grant the residents crime-victim status so they could testify at the sentencing hearing and, perhaps, win compensation from Citgo. Rainey granted that status on Sept. 14 and postponed the hearing.

In a court filing Wednesday, lawyers for the 15 residents are seeking $80,000 from Citgo for medical screening.

They also want Citgo to establish an $11 million trust fund for treatment of cancer or other illnesses suffered by the more than 300 people who have submitted victim impact statements to the court. A court-appointed special master would decide whose expenses should be covered.