Life seemed normal at the park in Porter Ranch on Tuesday, as women power walked the perimeter, parents pushed toddlers in swings, men counted off pull-ups on an exercise bar.
But hours later, authorities closed the gates to Holleigh Bernson Memorial Park and strung yellow tape to keep the public away until Southern California Gas Co. crews could scrub away an oily residue found on playground equipment.
Discovery of the residue was just one of many lingering effects of the largest natural gas leak in U.S. history. The gas company plugged the leaking well in Aliso Canyon three weeks ago, four months after it was reported, and many of the thousands of displaced families have moved back to this master-planned community.
But issues remain.
Some people moving home are finding small, brown droplets of oil on their homes and cars. The oil was probably forced out of the leaking well known as SS-25 during the repair process, and gas company crews installed screens near the well in January to prevent further spread of the mist, according to the company.
By then, however, many homes were covered in the residue. The gas company announced this week that it will clean at least 140 of those homes.
"We are committed to helping communities affected by the leak return to normal as fast as possible, and when residents expressed concerns about brown spots at local parks, we immediately mobilized crews to address the issue," said Gillian Wright, vice president of customer service for the gas company.
The Los Angeles County Department of Public Health received more than 700 illness complaints, including headaches, upset stomachs and respiratory issues, during the leak. Health officials blamed mercaptans, an odorant added to the methane, for those symptoms.
But in the weeks since the leak stopped, more than 300 people called the Department of Public Health to report continued health problems.
Given that air quality appears to have returned to normal levels, "this is relatively unexpected," said Cyrus Rangan, director of the Bureau of Toxicology and Environmental Assessment for the health department. "With these mounting reports of symptoms from the community, we want to make sure we respond effectively to it."
Health officials will conduct a door-to-door survey March 10-12. The goal is to better understand the health issues Porter Ranch residents are experiencing now that they're moving back.
Two air quality agencies are continuing to monitor the Porter Ranch community. The South Coast Air Quality Management District found methane levels there exceeded 3 parts per million on at least 14 days at multiple locations after the leak stopped. AQMD officials say those readings exceeded what the agency considers "typical" but were not high enough to be a health concern.
Residual methane in the soil near the well may have caused the increases at some locations but the cause of the other readings is unclear, the air district said.
Acting on a tip from a resident, a two-person team from the county health department visited Holleigh Bernson park Sunday to look for oil residue. The crew said it did not find anything, but two days later, staff members from L.A. City Councilman Mitch Englander's office visited the park and found oil on the playground equipment.
Prolonged contact with the oil can cause skin irritation, health officials say.
Rangan said he "can't really explain what occurred" when his inspectors gave the all-clear at the park.
As a precaution, the gas company was expected to clean three other neighborhood parks.
"At this point, with everything we've been through and this community has been through, I'm not taking anybody's word," Englander said.
Complaints about oil residue had been circling on social media. The president of the Porter Ranch Neighborhood Council said she asked gas officials to clean the parks three or four weeks ago as a proactive measure.
"It's extremely frustrating that families continue to be the ones to go home, find issues to be resolved — and then everyone reacts to that," Paula Cracium said.
She's pushing health officials to study the air quality inside Porter Ranch homes.
"Hopefully we find nothing but if we find something, that's the beginning of a process, not the end," she said.
As of March 6, there were 2,706 households still in temporary accommodations. Southern California Gas Co. will stop paying the expenses of relocated families March 18, a date the gas company was forced to accept after attorneys for Los Angeles County took legal action to provide customers with more time to move home.
On Tuesday, County Counsel Mary Wickham told the Board of Supervisors they may file for another extension if the experts in the field find "pertinent issues" that would warrant it.