A limited partnership was formed consisting of Arnold as general partner and Johnson and Howard as the limited partners. The limited partnership was organized in strict compliance with the limited partnership statute. Johnson was employed by the partnership as a purchasing agent. Both Johnson and Howard consulted with Arnold with respect to partnership business, voted on a change in the nature of the partnership business and disapproved an amendment to the partnership agreement proposed by Arnold. The partnership experienced serious financial difficulties and its creditors seek to hold Arnold, Johnson and Howard personally liable for the debts of the partnership. Who, if any, is personally liable?