This is Part 2 of a four-part series on an asbestos-tainted insulation called Zonolite, a killer that lurks in the attics and walls of millions of homes.

DENVER (Nov. 29) -- The government repeatedly insists that the millions of people with asbestos-contaminated vermiculite insulation in their attics are safe if they don't disturb the lethal material. Tell that to 71-year-old William Cawlfield, who has mesothelioma, a cancer that sometimes takes decades to surface and claim its victims.

Last month, Cawlfield stood outside the two-story red-brick farmhouse that had been his family's home for more than a century. He watched a man and a woman wearing respirators and dressed head to toe in Tyvek carefully remove something deadly from inside. He was paying $15,000 to have them do so.

Testing conducted at Cawlfield's old house in Pueblo, Colo., by the Environmental Protection Agency's Denver regional office found that high levels of the lethal fibers were released from the Zonolite insulation that was spread between the rafters in its attic.

Cawlfield was 15 when he and his father installed the Zonolite insulation.

"I used to play up there and kept my toys and a bunch of books because it was like a sand pile where I could hide things," he said, "because I had no idea that the asbestos was in it."

This lack of knowledge could be the reason he has undergone three surgeries to keep himself alive.

Cawlfield wasn't hurting at first. No pain or symptoms at all. But after repeated reminders from his wife and sister of a family history of heart disease, he found himself beneath an elaborate X-ray machine having his heart scanned for calcium build-up.

His heart was fine, he says, but a couple of enlarged lymph nodes popped up during the scan.

He bounced between Denver's large hospitals, enduring whatever X-rays, scans and sonograms each expert had to offer. Finally, a radiologist subjected him to a positron emission tomography, or PET, scan and found something.

"Well, your abdominal cavity lights up like a Christmas tree. If you were a woman I'd say you have ovarian cancer," Cawlfield recalled being told.

It turned out to be peritoneal mesothelioma -- a rare cancer in the lining of the abdomen. Usually, mesothelioma is found on the internal chest wall or the outer lining of the lungs. But wherever it surfaces, asbestos exposure is almost always the cause. The disease can take 20 to 40 years to surface, but it kills quickly.

After the diagnosis, Cawlfield filled three clean jars with dry, silvery, dime-size pieces of the vermiculite and took them to a Denver lab for analysis. It was the same lab used by the EPA. Within 24 hours, both the lab and EPA had called about what was in his attic.

In the 1970s and '80s, W.R. Grace & Co., which mined the vermiculite ore used in Zonolite insulation, and the Canadian military and EPA contractors ran experiments to measure asbestos released from Zonolite. They all, even Grace's scientists, found that even the most minor, gentle disturbance of the insulation sent dangerously high levels of asbestos fibers into the air and breathing space. So it was no surprise in 2008 that the EPA's Denver team, which had spent years working to define and quantify the toxicity of the asbestos mined in Libby, Mont., leaped at the opportunity to evaluate Cawlfield's house.

AOL News obtained the report on the EPA's findings and much of the internal correspondence. One e-mail called the house an "important living laboratory" on how the deadly fibers from Zonolite spread through an old house.

Wearing air-collecting filters, protective clothing and respirators to keep the fibers from being sucked into their lungs, the EPA team simulated everyday activities.

One person swept the floor. Another sat in front of a television for three hours, getting up several times to mimic grabbing snacks from the kitchen.

Some of the levels of asbestos recorded in the house exceeded the maximum number of lethal fibers that the Occupational Safety and Health Administration says is too dangerous for workers, the report showed.

"The asbestos levels found in the testing and sampling of the Pueblo house were very high and just makes many of us even more concerned about the hazards that exist in millions of other homes where people have no clue about the danger from Zonolite in their attics," Dr. Aubrey Miller told AOL News.

Miller was the medical officer on the EPA team that responded a decade earlier to reports of more than 400 asbestos deaths and thousands of illnesses from the tiny town of Libby, where the vermiculite was extracted from the Grace mine. He also participated in the evaluation of Cawlfield's house.

Although old, the house was in better condition than many of that age, inspectors concluded. Nevertheless, the almost-invisible asbestos-containing dust from the Zonolite sifted though the light fixtures and switches and ceiling fans and the seams of dried-out joint tape.

The EPA experts took air samples as they pretended to install a junction box and cabling in the attic.

Cawlfield, who designed custom installations of home theaters, speakers and other electronic systems, worries about the safety of those who install those systems or TV and phone cables, house renovators and even firefighters.

"We have these kids -- 25-year-olds -- in these attics, running wires, doing installations and repairs, crawling through this Zonolite without respirators or a care in the world. Because EPA never told them it could kill them," he said.

"And, like the vermiculite miners in Libby, they bring that stuff home on their clothes, exposing their children and spouses to that poison, and now we'll have another generation sick from this Libby asbestos."

Cawlfield became angry as he denounced EPA headquarters for doing little to warn workers and public.

"Ten years after the deaths at Libby were finally realized and all EPA has done is set up a website on Zonolite. How does the average homeowner or worker even know it's there to look at?" Cawlfield asked.

When asked why EPA hadn't and isn't doing more to warn the public, the physician, Miller, who is now senior medical adviser for the National Institute for Environmental Health Sciences, said to call EPA headquarters.

However, the EPA refused repeated requests for an interview.

EDITOR'S NOTE: For more than a decade, two-time Pulitzer Prize-winning investigative reporter Andrew Schneider has followed the saga of the tiny town of Libby, Mont., the asbestos-tainted vermiculite that was mined there and W.R. Grace, the company that shipped the lethal ore throughout the world. Schneider broke the story while with the Seattle Post-Intelligencer, and followed it in the St. Louis Post-Dispatch and The Baltimore Sun. Schneider and David McCumber authored "An Air That Kills." In this four-part report, AOL News' senior public health reporter examines the government's history of neglect in informing the public about the dangers of a killer than lurks in the attics and walls of millions of homes.

Part 3: 'In Libby, There Was No Maybe' About Dangers