Every day Southern California hospitals unleash millions of gallons of raw sewage into municipal sewers.
The malodorous muck flows miles to one of the region's sewage plants, where it is treated with the rest of the area's waste and then released as clear water into a stream or directly to the Pacific.
Scientists at the Environmental Protection Agency recently announced they had discovered a lethal superbug — the same one that caused outbreaks at UCLA and two other Los Angeles-area hospitals — in sewage at one of those plants. They declined to name the facility.
EPA scientists did not test treated wastewater flowing out of the plant to determine whether it still contained CRE, or carbapenem-resistant enterobacteriaceae.
But a growing number of studies show sewage plants can't kill the superbugs. Instead the facilities serve as "a luxury hotel" for drug-resistant bacteria, a place where they thrive and grow stronger, said Pedro Alvarez, a professor of environmental engineering at Rice University, one of the scientists studying the problem.
Alvarez and other researchers say the failure of sewage plants to eliminate the dangerous bacteria is one way they may be spreading from hospitals to the environment.
"Chlorine is just not doing it," Alvarez said of the treatment used by most plants.
The fear is that healthy people otherwise not at risk from the bacteria — including swimmers at the beach — could be infected.
Already officials are worried about the surprising number of people sickened with CRE who have not recently visited a medical facility: 8%, according to an October study.
Hospitals are not breaking laws by releasing the sewage. Laws regulate the overall level of disease-causing bacteria in the nation's surface waters, but there is no specific regulation of bacteria resistant to antibiotics.
Deemed the "nightmare bacteria" by federal officials, CRE survives nearly all antibiotics. It kills as many as half its victims.
Government officials, including those at the federal Centers for Disease Control and Prevention, say they are monitoring the wastewater studies but have so far made no recommendations to hospitals about the treatment of sewage that may harbor CRE.
"The prevention and control of CRE is an evolving process," said Melissa Brower, an agency spokeswoman. "CDC will continue to assess the appropriateness of this as new information becomes available."
Researchers have tried for years to raise the alarm about hospital sewage. The sludge includes not just waste from patients suffering from drug-resistant infections but also high levels of antibiotics prescribed to treat them.
As the sewage mixes, the antibiotics kill off weaker bacteria, leaving the more lethal ones to thrive. The bugs reproduce rapidly, and different species can swap genes, transferring their ability to withstand the drugs.
Last year, the nation's treatment plants were alerted to the risks of untreated medical sewage when a few American hospitals began caring for patients who had been struck by Ebola in Africa.
The CDC directed hospitals to allow the Ebola patients to use the toilets in their rooms, but said sewer workers should wear protective clothing, including goggles and a face mask, to protect themselves from the highly contagious virus.
Concern about that case prompted a foundation supported by water utilities to study what contaminants, including bacteria, hospitals are releasing in sewage.
"The idea of CRE flowing down our sewer pipes gets me nervous," said Dr. James McKinnell, an infectious disease expert at the Los Angeles Biomedical Research Institute, who has been working to stop superbugs from spreading. "We should be testing our runoff."
Inside hospitals, staff go on high alert when a patient tests positive for CRE.
Infected patients are isolated. Nurses don protective gowns and gloves. Family and friends are warned about visiting.
So far at least 75 of the 100 hospitals in Los Angeles, Orange and Ventura counties have reported patients infected with CRE. Los Angeles has the state's highest rate.
CRE thrives in water. Hospitals have found it living in sink drains. The bacteria are happy in patients' intestines and it passes through in urine and waste.
Every day, 2 million gallons of raw sewage from Los Angeles hospitals flows to the city's Hyperion treatment facility.
The Disneyland-sized complex of pipes, giant tanks and pools sits at the edge of the Pacific, near Los Angeles International Airport.
Like other plants, Hyperion intentionally creates an ideal environment for microorganisms to thrive. The plant mixes non-disease-causing bacteria into the sewage and pumps in oxygen, allowing the bugs to feed and break down the waste.
The solids are settled out, and the clear water is piped five miles offshore and released 190 feet below the waves. It is treated with chlorine only in rare cases when it is released a mile offshore.
Hyperion employees test the treated water for levels of bacteria, but do not hunt for those that resist antibiotics like CRE.
Timeyin Dafeta, Hyperion's manager, said that if CRE was present it "would be in extremely low concentrations" because hospital sewage accounts for just 0.5% of the city's wastewater.
"We have no indication the effluent is coming back to impact the shoreline," Dafeta said.
Farther south, dozens of other sewage plants release treated wastewater into creeks and concrete channels that eventually flow into the Pacific.
Some surf spots — like the Santa Ana River jetties in Orange County — have become known as places with great waves that can make you sick.
"Just check yourself for cuts prior to entering," the surfing magazine Stab recently warned about the site on the northern border of Newport Beach. "Oh, and keep your mouth shut."
California officials don't know what bacteria is in the seawater. They monitor the ocean water for what they call fecal indicator bacteria — a sign of raw sewage. But they rarely test for specific bacteria, including those that are drug-resistant.
A 2010 study estimated that 689,000 to 4 million people are struck by gastrointestinal illnesses caught from Southern California beaches each year. An additional 693,000 are sickened with respiratory problems.
In December 2014, Barry Ault died on Christmas morning a few days after surfing off Sunset Cliffs in San Diego. A staph infection attacked the 71-year-old's heart valve, which had been replaced 10 months before.
Ault's friend also got seriously ill. The two went surfing just after a rainstorm when it's not possible for sewage treatment plants to handle all the runoff.
Sally Ault, Barry's wife, said that the two were surfing in an area known for not being polluted. She said her husband, who grew up in Arcadia, had fully recovered from the earlier heart operation and was in great shape.
"It was nothing other than the bacteria," she said.
It's difficult to find which regulatory agency is responsible for monitoring what hospitals release to the sewers.
The state public health department referred questions to State Water Resources Control Board officials. That agency referred questions to county officials, who said they had made no recommendations to hospitals to pre-treat sewage from CRE patients.
Enrique Rivero, a spokesman for UCLA, where three patients died after being infected by CRE from a contaminated medical scope, said that no one was available to comment.
A spokesman at Cedars-Sinai, site of a similar scope-linked outbreak, said the hospital follows all regulations relating to the handling of patient waste.
Cathy Milbourn at the EPA said agency scientists believe there is "insufficient information available to reach a definite conclusion on the presence and fate" of drug-resistant bacteria in sewage plants.
Last fall, a team of EPA scientists reported that they had found CRE in sewage at treatment plants across the country — including one in Southern California and another in the northern part of the state.
"I tested seven different plants and I found it in all of them," said Jill Hoelle, a scientist in the EPA's office of research and development.
The scientists concluded that CRE is "widespread" in America's sewage — a finding that Hoelle said she found surprising given that reported patient infections are still relatively rare.
Alvarez, the Rice professor, said that with the rise of ever more dangerous bacteria like CRE, there is a risk of returning to a time, before the invention of water treatment, when infectious diseases were a major cause of death.
"We can save more lives by treating water than doctors can," he said.