Physical Demands: Tasks require the ability to exert heavy physical effort in heavy work, with greater emphasis on climbing and balancing, but typically also involve some combination of frequent lifting, standing, walking both normal and uneven sometimes slippery surfaces, bending, stooping, kneeling, crouching, crawling, pulling, and carrying, pushing, and/or pulling of moderately to extremely heavy objects and materials (20-125 pounds); may occasionally involve even heavier objects and materials (up to 200 pounds). Performance of essential functions may require exposure to adverse environmental conditions, such as dirt, dust, pollen, odors, wetness, humidity, rain, fumes, temperature and noise extremes, machinery, vibrations, electric currents, traffic hazards, bright/dim light, hazardous materials, toxic agents, violence, disease, or pathogenic substances.