State officials did not tell Gov. Deval Patrick on the public for nearly six weeks after the light fixture fell.
BOSTON – State Transportation Secretary Jeffrey Mullan said investigators are close to determining what caused a corroded 110-pound light fixture to fall from the ceiling of a Big Dig tunnel in February.
Mullan told a legislative committee Tuesday the corrosion may have been started by contact between two different kinds of metal in the light fixture, and made worse by salt from snow and ice removal efforts.
No one was hurt when the fixture crashed to the roadway but it prompted a review of about 25,000 in Big Dig tunnels. Mullan said fewer than 2 percent were found to have similar problems.
Mullan said it has not yet been determined if the corrosion resulted from a design or installation flaw. But he said the state could go after contractors for the cost of replacing the defective fixtures.