DETROIT, May 29 (Reuters) - Ford Executive Chair

Bill Ford on Thursday sounded the alarm on the potential for

Washington to do away with production tax credits that support

the manufacturing of electric vehicle batteries.

The disappearnce of the credits would threaten Ford's

investment in a Marshall, Michigan, plant. "If it doesn't stay,

it will imperil what we do in Marshall," Ford said at a policy

conference in the state.

"We made a certain investment based upon a policy that was

in place. It's not fair to change policies after all the

expenditure has been made," he said.