The Aliso Canyon nightmare isn’t over for Sandy Crawford’s family and hundreds of other refugees from the methane leak in Los Angeles County.

Although the 112-day leak from an underground gas reservoir was permanently sealed more than a month ago, relocated residents returning to their homes report health symptoms similar to those that drove them out weeks earlier. Crawford’s two boys, ages 3 and 11, both got sick when the family moved home, and so did the family dogs, Betty and Blade. The Crawfords moved back to their hotel within days.

“The limbo is what’s killing us,” Crawford said. “Not knowing the long-term effect and not knowing if we are just going to take [our children] home and expose them to more stuff, and what it is that we are even exposing them to, it’s such an uneasy feeling.”

Since the leak was sealed Feb. 18, the Los Angeles County Health Department has received health complaints from nearly 300 individuals who either returned home or attempted to do so. The symptoms are similar to the 700 reports of headaches, dizziness, rashes, eye, nose and respiratory irritation, and abdominal pain from Oct. 28 to Feb. 18, when the leak was active. The causes haven’t been identified.

This has set up a clash between residents and Southern California Gas Co., the owner of the Aliso Canyon natural gas storage facility. The unit was the source of the largest natural gas leak in U.S. history. Under orders from state authorities, SoCal Gas has been paying to temporarily shelter more than 6,000 households from Granada Hills, Porter Ranch and neighboring communities. Public health authorities and SoCal Gas say air quality in those neighborhoods has returned to normal and residents can safely move back home.

The dispute is coming to a head this week. A state judge in LA County ruled Friday that the company is not required to pay for temporary quarters beyond Tuesday. SoCal Gas said it would pay hotel bills through checkout time this Friday. As of last Tuesday, roughly 5,000 families still hadn’t returned home from temporary housing, according to SoCal Gas spokeswoman Melissa Bailey.

“Air quality and health experts—including those from the county’s own public health department—have been saying for weeks that the air quality in the area is at normal levels, and is similar to the air quality in other parts of the county,” SoCal Gas said Friday in a statement. “Testing by a third party of over 70 homes, sponsored by SoCal Gas, showed no elevated levels of methane inside these homes, and did not detect mercaptans or other sulfur compounds associated with natural gas.”

The argument over environmental safety in LA echoes famous past disputes over the chemically tainted Love Canal neighborhood of Niagara Falls, N.Y., and water pollution in Hinkley, Calif., the subject of the film, “Erin Brockovich.” The mystery health effects show how difficult it can be for authorities to detect substances that sicken some people, or even to identify the causes of environmental illnesses.

Sandy Crawford, 39 and a vice president at a movie production company, and her family first returned to their home, a single-story ranch house on a quiet cul-de-sac in Granada Hills, on Feb. 19. They thought their troubles were over after more than a month in two adjoining hotel rooms. They had tired of eating cold cereal and microwaved eggs for breakfast. They wanted to resume hiking with their kids and dogs in the hills above their home and to quit driving an extra 20 miles to their hotel at the end of each day.  

Before moving back home, Sandy and husband Alan, 46, an audio engineer, hired professional cleaners to scrub the house—twice. They opened doors and windows to air out the house, and ran air filters continuously for two days.

The next day, their 3-year-old son Diesel woke up and said he couldn’t breathe. Before leaving their home in January, the whole family experienced respiratory issues from bronchitis to asthma attacks that required visits to urgent care. Diesel and the others were free of symptoms while in the hotel.

In the following days, Sandy started having abdominal pain. Chancellor, the 11-year-old, began coughing up brown phlegm. His nose, throat and eyes hurt. The Crawfords had the gas company install air filters on their home heating and air conditioning system on Feb. 22. The next day Chancellor was too sick to go to school. 

With a couple of days left before the SoCal Gas funding for relocation housing was to end, they returned to their hotel on Feb 23. They returned to their home a second time on the evening of Feb. 25, the day their housing subsidy was set to expire. Housing subsidies were subsequently extended, but the court last week rejected a further extension. Within an hour of returning home the second time, however, Diesel said he wasn’t feeling well.

“I looked up at him, and there was just blood pouring down his face,” Sandy Crawford said, describing Diesel’s nosebleed.

Determining the cause of such ongoing illnesses is crucial for addressing the immediate and potential long-term health effects, according to public health authorities. No one knows what is causing the symptoms. Not everyone living near Aliso Canyon is affected, but for many residents, nothing short of leaving the area seems to make them go away.

“The symptoms that they are having now are difficult to determine in terms of what their origins may be,” said Cyrus Rangan, director of the Bureau of Toxicology and Environmental Assessment for the Los Angeles County Department of Public Health.

One cause of persisting illnesses may be an oily mist that was released from the leaking well, known as SS-25. In mid-December, residents started reporting an oily residue on their cars, patios and yards. Before it became a gas storage unit, Aliso Canyon was an oil reservoir. Trace amounts of oil remained underground and are believed to have surfaced with the leaking gas.  

“It appears that the substance was forced out of well SS-25 in the form of liquid droplets, along with the flow of natural gas emanating from the well,” wrote LA County Public Health Interim Director Cynthia Harding in a March 6 letter to LA County Supervisors.

The droplets may have entered nearby homes and may be responsible for ongoing health effects, according to one independent expert.   

“You are essentially getting very small droplets that become an aerosol that can then penetrate indoors and conceivably would deposit on substrates, surfaces and in walls,” said Michael Jerrett, professor and chairman of the Department of Environmental Health Sciences at the University of California, Los Angeles. “If that were the case, you could be looking at the delivery of toxic materials into the homes.”

Another possibility is the formation of “secondary aerosols,” volatile organic gases that, once emitted from the well, undergo chemical reactions in the atmosphere, Jerrett said. These reactions could result in conversion of the gases into particles that penetrate homes and lodge themselves into carpets, walls and other surfaces.

Vaporized oil droplets or secondary organic aerosols are the most likely source of “something that would have biologically meaningful capacity to deliver a dose and still be toxic and potentially capable of eliciting some of the effects that people are reporting,” Jerrett said.

Officials with the Los Angeles County Health Department initially said the oily mist did not pose a significant threat.

Tests of residue deposited by the mist determined it consisted of “relatively long-chain hydrocarbons found in crude oil,” the department’s Harding wrote in her letter to county supervisors. “Based on the chemical composition and physical state of the residue, it presents minimal risk.”

County health officials have since spoken with Jerrett and are giving his theory of vaporized droplets and aerosols serious consideration.

“Chemical transformation is something we are considering,” said Angelo Bellomo, deputy director of the department’s protection division. “We’re continuing to talk with [Jerrett] because we think his work is very important to helping us understand what could be going on.”

Jerrett began independent in-home air testing two weeks ago. Preliminary results found elevated levels of benzene and hexane in two of seven homes tested, although it is unknown whether the levels are high enough to pose a health concern, according to a statement by the county health department on Saturday.

The department is working with Jerrett and the U.S. Environmental Protection Agency’s Indoor Air Quality Program to develop its own in-home testing, to begin late this week. When completed, results of both sets of in-home tests will go far beyond the tests SoCal Gas did last week that checked only for methane and mercaptans, a class of odorants added to natural gas to help in detecting leaks.

Chemical Sensitivity

Another possibility is Multiple Chemical Sensitivity Syndrome (MCSS), in which people become sensitive to toxins at very low levels of exposure—levels that would not typically elicit an adverse reaction.

“If people have experienced the insult originally, then it may not take the same levels of exposure that would be a problem in a healthy person,” said Rodney Dietert a professor of immunotoxicology at Cornell University. “It can seem to be precipitated by fairly low doses.”

Health department officials, however, say MCSS is a theory that hasn’t been proven.

“We don’t really have that kind of evidence that would suggest that people would be exposed to these compounds and then have this sort of elevated level of sensitivity at a later time,” Rangan said.

Rangan’s view corresponds with that of the American Medical Association.

“A report presented to the American Medical Association in 1991 from one of its advisory councils found no scientific evidence that supports the contention that Multiple Chemical Sensitivity Syndrome (MCSS) is a significant cause of disease,” AMA spokesman Robert Mills said. Until “accurate, reproducible, and well-controlled studies are available, the AMA Council on Science and Public Health believes that multiple chemical sensitivity should not be considered a recognized clinical syndrome.”

Dietert said much of the controversy over MCSS reflects the medical profession’s lack of understanding of how different people respond to chemical exposures at different levels.

“If we’re not smart enough to figure out all the things that go into it, it doesn’t take away from the fact that they are experiencing those symptoms,” Dietert said.

While causes aren’t well understood, people with MCSS typically have some loss of function of barrier tissues such as mucous membranes in the nose, he said. That allows chemicals from the environment to more easily penetrate underlying body tissue.

“How you get to that from a gas leak event is still a bit of an open question,” Dietert said.  

Before determining whether chemical sensitivity is to blame, it’s important to know more about what residents are being exposed to when they return to their homes, said Janette Hope, a physician in Santa Barbara, Calif., who treats patients for chemical sensitivity and is the past president of the American Academy of Environmental Medicine.  

“I would definitely want to make sure that their home and indoor and outdoor environments are clean and safe for them before I would describe it as simply chemical sensitivity to very low levels,” Hope said. “I would need to be confident that they weren’t being exposed to toxic levels, and I don’t know if that has been looked at.”

LA County Health Department officials are seeking an extension of several more weeks to complete their indoor air monitoring.

If the Crawfords’ dogs, who have been at home since their relocation approval ran out a month ago, are any indicator, something still may  not be right. Betty, the family’s 4-year-old boxer, has thrown up five times since returning home. Blade, the 4-year-old Chihuahua, recently started panting excessively, coughing and having trouble breathing.

As health experts try to determine the cause of the lingering illnesses, residents are unsure what to do. The Crawfords had their home cleaned a third time, took down the curtains, threw out a carpet and replaced a mattress and all of their sheets, all at their own expense. They tried moving back home a third time last Monday.

Although no one got sick again, the family left Wednesday after a radon detector registered an elevated level of the radioactive gas, which can cause cancer after long exposure. There’s little evidence of elevated radon in the neighborhood, and the Crawfords say they don’t know what to make of the reading.

“I don’t really know if we are going to go home and be safe again,” Sandy Crawford said. “It’s the one place that you are supposed to be able to go and feel safe and you don’t.”