The employee frequently is required to stand, sit, walk, climb, use manual dexterity to operate tools used in the course of work and typical office environment, hear sufficient to hear conversations in person and via telephone and radio, and vision sufficient for distance sight and to read diagrams, computer screens, manual reports, rules, regulations, laws and plans. The employee must be able to maintain constant alertness to the multiple concurrent activities occurring at the site, including the activities of other employees and contractors, the operation of stationary equipment and the movement of mobile equipment.