A MAJOR review of Boston's 'Big Dig' highway tunnels project was announced last month after a 3t section of concrete fell from the roof of the 190 connector tunnel killing a woman on 10 July.
Massachusetts' governor Mitt Romney ordered the review of construction of roads, bridges and tunnels on the $15bn (£7.9bn) project.
It will be carried out by a yet-to-be-appointed engineering consultant.
The news comes after the Bechtel/Parsons Brinckerhoff joint venture managing the scheme called for the entire project to be reviewed (GE August 2006).
Since the collapse, anchors in the concrete roof panels have been doubled and the section of tunnel was reopened on 10 August.
A spokesman for the tunnel operator, the Massachusetts Turnpike Authority (MTA), said: 'We are in the midst of installing steelto-steel connections where possible, and where that's not possible we are using mechanical bolts. The second connection provides redundancy for the first.'
Since the collapse it has emerged that the MTA had warned against use of epoxy resin grouted anchors - thought to be responsible for the collapse - five years ago.
Instead, the MTA recommended embedding a rebar connection from the roof of the tunnel into the concrete of the suspended ceiling.