DOVER, N.H. – A New Hampshire lawyer is representing 85 New England families that claim a mercury-based compound in vaccines caused autism and other disabilities in their children.

Michael Noonan said thimerosal, used for decades as a preservative in childhood vaccines, is a neurotoxin that damaged thousands of children.

Studies that have tracked thousands of children have found no association between autism and thimerosal. That hasn’t dissuaded critics, who claim the studies are flawed.

Noonan said a big increase in autism in the 1990s coincided with an increase in the number of vaccinations children received. Several injections during a single doctor’s visit hit their developing nervous systems with too much mercury, he said.

“Thimerosol was never used to enhance the vaccine or because it was good for kids,” he noted.

Some of those suing have videos of their children behaving normally the day before a medical visit, then regressing the next day, demonstrating “specific cause and effect,” Noonan said.

The families he represents include some children with severe disabilities, he said.

Since 2001, all vaccines given to children 6 and younger have been either thimerosal-free or contained only trace amounts of the preservative. Thimerosal has been phased out of some, but not all, adult vaccines as well.

Most doses of the flu vaccine still contain thimerosal, though manufacturers produce versions free of the preservative for use in children.

Nationally, 5,200 legal claims of damage from childhood immunizations are pending, mostly involving boys. Those suing are seeking money from the Vaccine Injury Compensation program, a government insurance pool funded by a vaccine tax. At a hearing in June, a special master, or judge, is expected to decide whether thimerosal caused autism and other disabilities critics associate with it. The U.S. Department of Justice will defend the fund and vaccine manufacturers.

If his clients and others are successful, that could open the door to individual trials.

Noonan said he would represent many more people if New Hampshire did not have a three-year deadline for lawsuits based on immunizations. He hopes the next Legislature will extend the deadline.

“It’s horribly unfair,” he said. “In New Hampshire, if a child is injured in any other way, the statute of limitations isn’t until two years from their eighteenth birthday.”