Ask Lynn Hartman about the homeland security bill, and her face curls in disgust.

It's not that she has anything against fighting terrorists; after all, her husband, Dave, is a pilot for United Airlines.

But the new legislation hits close to home for the Hartmans in another, even more personal way. Their 21/2 -year-old son, Taylor, is autistic.

Connecting autism and domestic security is a stretch, but Congress managed to do it last month. Last-minute add-ons to the homeland security bill grant Eli Lilly & Co. immunity from lawsuits related to its product thimerosal, a mercury-based preservative used in many vaccines.

The Hartmans believe it is responsible for Taylor's autism.

"He's been mercury-poisoned," Lynn Hartman says.

The Hartmans are not alone. In a speech before Congress on Nov. 22, Rep. Dan Burton, R-Ind., said he had "heard from thousands of families across the country that this same thing happened to their child." He cited a growing body of evidence that suggests a huge spike in the number of autistic children may be linked to a program of infant vaccinations that began in the early 1990s.

Like most babies since then, Taylor was vaccinated very early in life -- much earlier than you and I. He had had several doses of thimerosal before he was 6 months old.

Large, active and healthy at birth, Taylor developed normally. He was walking and beginning to talk by the time he was 14 months old. But then his parents, who live in Sonoma, noticed a sudden, troubling change.

"He started having temper tantrums," says Lynn. "He stopped talking. He became adverse to touch."

Autism is a tricky thing to pin down. Symptoms can range from withdrawal and difficulty speaking to violent, self-injurious behavior. It once was classified as a mental illness passed on genetically to children.

The past 10 years, though, have included a large increase in the number of cases of "late-onset autism" -- symptoms of the disorder that appear in young children who previously have been "normal."

The cause is the subject of intense debate. While mercury is often pointed to as a likely culprit, it is a naturally occurring element that enters the body in a number of ways. Seafood, dental fillings and various pollutants all contain mercury.

Although researchers have called it "biologically plausible," no study has definitively linked thimerosal with autism. But because of the risks posed by mercury, federal health officials in 1999 advised that infants not receive vaccines containing thimerosal until they were 6 months old. Most vaccines no longer contain it.

But Taylor's vaccines did.

Traditional treatment for autism involves a lot of occupational therapy, special education and drugs. But the Hartmans have followed a protocol suggested by Stephanie Cave, a Louisiana pediatrician who believes high doses of mercury compromise some children's ability to leach metals from their bodies. Taylor, for instance, had extremely high levels of copper, arsenic, mercury and other metals in his tissues.

They began treating him metabolically, using diet and supplements to remove the metals from his body. The regimen, the Hartmans say, has given them their son back.

Taylor's blue-gray eyes peek out from under thick, curly bangs. He points out shapes in the painting he's working on and explains them to a visitor: "wee" and "see."

"He started talking again about a month and a half ago," Lynn Hartman says. She says his "development age" is about 19 months -- behind, but progressing once again.

She says her anger about the homeland security bill is not because she wants to sue, but because it sweeps a problem under the rug.

"A lot of these kids can get better, but they need to get help now," she says. "The drug companies need to admit they messed up."

Contact Chris Coursey at 521-5223 or ccoursey@pressdemocrat.com.