Physical Ability: Tasks involve the ability to exert very heavy physical effort in very heavy work, typically involving some combination of climbing and balancing, stooping, kneeling, crouching, and some lifting, carrying, pushing and/or pulling of persons, objects and materials of heavy weight (up to 100 pounds). Environmental Factors: Some tasks may require exposure to adverse weather conditions, temperature extremes, wetness/humidity, dust/pollen/smoke, harsh chemicals/cleaning agents, equipment hazards, communicable disease, strong odors.