From the Chronicle-Tribune (Marion):
Q: The board of works has been meeting but is having a problem reaching a quorum. Even though they have no quorum, the two members present have been signing off on payments to be made. Can they do this?
A: The board of works can ratify their actions at a meeting where a quorum is present. In effect, the two are acting as agents of the entire board, and it is assumed they are acting on the board’s behalf.
The only danger is that if a bill the two have agreed to pay becomes a matter of dispute when the entire board meets. The vendor isn’t going to want to pay the money back, and the two members who approved the payment aren’t going to want to reimburse the city for the disputed amount.