Environmental Factors: Performance of essential functions may require exposure to adverse environmental conditions, such as dirt, dust, pollen, wetness, humidity, rain, fumes, unsafe structures, heights, confined spaces, machinery, vibrations, electric currents, traffic hazards, animal/wildlife attacks, or animal/human bites. PERFORMANCE APTITUDES: Physical Abilities: Tasks require the regular and, at times, sustained performance of moderately physically demanding work, typically involving some combination of climbing and balancing, stooping, kneeling, crouching, and crawling, and that may involve the lifting, carrying, pushing, and/or pulling of moderately heavy objects and materials (20-50 pounds).