By Jim Clark

The Massachusetts Bay Transit Authority said today that the budget for the Green Line extension into Somerville and Medford is short by as much as $1 billion.

State transportation secretary Stephanie Pollack is saying that officials are considering modifications to the plan, and even a possible cancellation of the project, which she indicated was not a desirable option.

Partial funding by the Federal Transit Administration is a key component in seeing the project through, but that funding is now questionable in light of the budgeting shortfall, according to reports.

A number of reasons for the budget discrepancy were cited by Pollock, including the fact that initial cost estimates were calculated during the lowest dip in the recent recessionary period, which have now been inflated.

Interim general manager of the T, Frank DePaola, also cited some of contracting methods that the T has not been using in the past as a contributing factor.

No final decisions have yet been made on the project, and all options are currently being studied.