All sense of survivors’ guilt was fleeting for those residents whose homes remained standing after wildfires ripped through the Los Angeles area three months ago.

Many worried that smoke from the Eaton wildfire that destroyed more than 9,000 structures and killed 18 people may have carried toxins, including lead, asbestos and heavy metals, into their homes. But they struggled to convince their insurers to test their properties to ensure it was safe to return.

Nicole Maccalla, a data scientist, said embers burned more than half of her roof, several windows and eaves were damaged, and her house in Altadena was left filled with ash, debris, soot and damaged appliances. She said her insurance adjuster said USAA would pay for contamination testing, but after choosing a company and coming back with the results, her claim was rejected. The adjuster said the company only covered testing in homes with major damage.

“Every single item is a battle,” said Maccalla. “It’s denials and appeals and denials and appeals, and you wait weeks and weeks and weeks for responses.”

Maccalla and others banded together as Eaton Fire Residents United, sharing indoor environmental testing data and compiling the results in an online map. Of 81 homes tested so far for lead, all show elevated levels, according to the group.

“I’ve already had multiple people reach out and say: ‘Thank you for publishing this map … because my insurance company has changed their mind and approved testing,’” said Maccalla, who helped design the data collection to verify results and maintain privacy.

Many homeowners paid privately for the testing after their insurance companies refused, revealing gaps in coverage. The group hopes the data will help residents who can’t afford it to convince their insurers to cover testing and remediation.

“If I can prove my community is not fit for human habitation then maybe I can show my home won’t be,” said Jane Lawton Potelle, founder of Eaton Fire Residents United.

It’s not easy to understand how and when it is safe to return home, Potelle said. The fine print of insurance policies can be frustrating and confusing, and the government has not stepped in to help.

The Federal Emergency Management Agency said it has no plans to conduct widespread environmental testing. The Los Angeles County Department of Public Health is tracking environmental testing largely by academic researchers and a handful from government agencies, but most studies assess outdoor contamination.

Reports from other urban wildfires, in which building materials, appliances, cars and more burn at incredibly high temperatures, show increased levels of heavy metals including lead and polycyclic aromatic hydrocarbons (PAHs) such as benzene that are tied to negative health risks. But insurance companies haven’t standardized testing for those contaminants.

Home insurance broadly covers fire damage, but there is a growing dispute over what damage must be covered when flames don’t torch the property.

California Insurance Commissioner Ricardo Lara released a bulletin in March that put the onus on companies to properly investigate reported smoke damage, saying they cannot deny such claims without investigating thoroughly, including paying for professional testing as warranted. But many residents have been left to fight for coverage anyway.

Janet Ruiz, spokesperson for the Insurance Information Institute that represents many major insurance companies, said it’s hard to compare neighbors because every claim is unique due to each home’s physical structure, actual damage and defined insurance coverage limits.

“It can vary and insurance companies are sensitive to what the claim is,” Ruiz said. “You have to work with your insurance companies and be reasonable about what may have happened.”

Dave Jones, director of the Climate Risk Initiative at University of California, Berkeley, and former state insurance commissioner, said testing should be covered even though some insurance companies disagree.

“It’s perfectly reasonable for people to have some kind of environmental test done so that their home is safe and their property is safe,” Jones said. “We’re talking about very catastrophically high temperature fires where all sorts of materials are melted and some of them become toxic.”

The state’s insurer of last resort, known as the California Fair Access to Insurance Requirements Plan, has been scrutinized for years over how it handles smoke damage claims. A 2017 change to the FAIR Plan limited coverage to “permanent physical changes,” meaning smoke damage must be visible or detectable without lab testing for claims to be approved. State officials said that threshold was too high and illegal, and ordered a change.