BOSTON -- Insurance companies would be forced to cover most of the prosthetic limb costs for amputees under a bill passed by the state Senate yesterday.

The bill, which still needs to be passed by the House of Representatives, would require insurers to cover prostheses at the same level as Medicare.

That means insurers would be forced to cover 80 percent of a prosthetic limb's price tag, excluding an annual deductible. The measure would be a boon to the many amputees who have private insurance plans that only cover a limited amount of costs for prostheses per year.

"When you buy insurance, you expect it to cover these catastrophic things," said Keith Cornell, owner of Cornell Orthotics & Prosthetics in Salem. "(But) prosthetics are one of those things that have fallen through the cracks."

Cornell said most private insurance plans typically only pay for a small portion of the costs for prostheses, which could range from a few thousand dollars to more than $30,000.

After learning the Colorado Legislature had passed a similar bill, Cornell started pushing for the measure here in Massachusetts two years ago.

The effort later gained momentum when Juliet Bryce, a Salem resident who has been using a prosthetic leg after losing her left leg in an accident last year, and her husband began advocating for the bill. They sought the help of their state lawmakers, Rep. J. Michael Ruane, D-Salem, and Sen. Frederick Berry, D-Peabody. Both legislators agreed to champion the cause at the State House.

"For whatever tragic reason one might lose a limb, that is overwhelming," Berry said. "Then to be faced with the extraordinary costs of buying another limb - it seems like a double tragedy."

Berry said the bill would only have a minimal cost on insurance companies because relatively few people in the state would need the coverage.

Still, Bryce's husband, former Salem city councilor Scott LaCava, is worried that lobbyists for the insurance industry may try to stop the legislation now that it's before the House, even though they have apparently been quiet so far.

"Frankly, I thought the insurance lobby would have tried to kill it by now," LaCava said. "They're kind of conspicuous in their absence. Maybe it's the quiet before the storm."

Lawmakers are running out of time to pass the bill in the House: Formal sessions at the State House are scheduled to end for the year on July 31.