For weeks, she has suffered unbearable headaches that she thinks may be caused by mold -- and now she's on the verge of spending thousands to fix the problem.

"I can't live in this house with this headache," said the 55-year-old woman who did not want her name or the Boston suburb where she lives disclosed for fear the value of her home would suffer.

She's not alone in her worries.

Mold and its potential hazards got a higher profile in recent years as insurers complained they were being flooded by mold cleanup claims.

The problem for insurers may be lessening, but the jury is still out on the true hazards of mold. And experts warn people to be aware and take common sense measures to avoid problems.

Mold can be found almost everywhere in nature. Various kinds of mold can be seen growing on spoiled fruit or old bread, while others play a beneficial role in the creation of beer and wine, cheese and the drug penicillin.

Experts say there are a variety of molds that can be found in homes. Problems arise when there's too much mold in the house and its spores fill the air.

Some experts say efforts to make buildings more energy-efficient have compounded the problem by making buildings more airtight, sealing in mold and raising moisture levels.

How harmful is mold? Federal health officials say molds have been associated with allergic diseases and can exacerbate asthma. But they say it's unclear whether molds can cause other dire effects that some have claimed, such as pulmonary hemorrhage or neurological problems.

News stories have told of people with harrowing health problems attributed to mold and others who took extreme anti-mold measures like bulldozing their homes. Celebrities like former talk-show sidekick Ed McMahon and environmental crusader Erin Brockovich drew more attention to the issue when they had mold in their homes.

With awareness rising, insurers saw rising claims from people who wanted companies to pay for mold cleanup. But that may now be subsiding, according to both the insurance industry and activists.

The number of mold-related claims reported to Policyholders of America, a consumer advocacy group, has seen a "huge decline," the organization's president, Melinda Ballard, said recently.

A key reason is that insurers have taken steps to change homeowners' policies to cut back on coverage for mold problems, Ballard said.

"It's mostly because: why file a claim if it's not covered?" said Ballard, who won a multimillion-dollar mold lawsuit in Texas, helping to make that state a hot-spot in the mold controversy.

P.J. Crowley, spokesman for the Insurance Information Institute, an industry-supported group, said, "In terms of the number of claims, we may have seen the peak."

Crowley also said the surge may have been caused by "emotionalism" surrounding the issue. But he warned that the decline in claims didn't necessarily mean the insurance industry is in the clear.

"Claims may be receding, but the risk is still there," Crowley said, pointing to estimates that there are thousands of lawsuits over mold still pending in the courts.

Insurers have moved to limit coverage for mold in 41 states, said Eric M. Goldberg, assistant general counsel of the American Insurance Association, which represents 424 companies.

"We're trying to establish a reasonable amount of remediation coverage and to make additional amounts of coverage available to those who want to pay for it," he said.

Mold has stirred up a storm of lawsuits with a variety of targets, including insurance companies, developers, the makers of building materials that get moldy, and some mold remediators who allegedly botch cleanups.

Some have said mold could become "the next asbestos," referring to the deadly cancer-causing substance that has spawned 600,000 lawsuits, caused dozens of bankruptcies and thrown tens of thousands of people out of work.

But Daniel Swartzman, a professor at the University of Illinois at Chicago and a practicing lawyer, said he believes the health risks associated with mold are less serious.

"I don't think they're comparable," said Swartzman who has handled both mold and asbestos cases. "I think people who say mold is the next asbestos are overreacting."

The controversy over mold may take a new twist in the fall, when a report reviewing scientific knowledge on mold's effects on human health is to be completed for the Centers for Disease Control and Prevention in Atlanta, according to CDC spokeswoman Bernadette Burden.

In the meantime, experts say there are simple measures that can help people prevent mold problems.

Ballard suggested that people check their attics and look under their sinks for water leaks. In the wintertime, she said, people should be diligent about cleaning out gutters so ice dams don't form and cause roof leaks.

Jeff May, a home inspector based in Cambridge who is an expert on mold and indoor air quality, said people should keep the humidity in their basements below 50 percent; be sure to fix water leaks, whether in the basement or attic; and keep basements as clean as other parts of the house.

May performed a battery of tests at the Victorian home in suburban Boston, scrutinizing the woman's damp, often-flooded basement and prescribing cures for drainage problems outside.

Mold, he later said, was everywhere, from the Oriental rugs upstairs to the inside of the heating system.

The woman said she was shocked, depressed and unsettled by his findings, but hoped he could find a solution.

"Mold has been making people sick forever," May said. "No one ever realized it was mold. It was that simple. It's a huge story because people are now becoming aware of it. ... We just have to get this place really, really cleaned up."