Environmental Factors: Performance of essential functions may require exposure to adverse environmental conditions, such as dirt, dust, pollen, odors, wetness, humidity, rain, fumes, smoke, temperature and noise extremes, hazardous materials, fire, unsafe structures, heights, confined spaces, machinery, vibrations, electric currents, traffic hazards, bright/dim lights, toxic agents, animal/wildlife attacks, animal/human bites, explosives, water hazards, disease, pathogenic substances, or rude/irate individuals. Physical Ability: Tasks require the regular and sustained, but not constant, performance of physically demanding work, typically involving some combination of climbing and balancing, stooping, kneeling, crouching, and crawling, and that generally involves lifting, carrying, pushing, and/or pulling of moderately heavy objects and materials (25-50 pounds); may occasionally involve heavier objects and materials (100 pounds or more).