dirt, cold, rain, and fumes), exposure to extreme heat/cold or extreme weather conditions, exposure to strong odors and/or smoke, exposure to strong and/or toxic chemicals, exposure to dust or pollen, and exposure to elements that can cause illness (e.g., pathogenic substances, virus, and parasites). Tasks involve the regular, and at times sustained, performance of heavier physical tasks such as walking over rough or uneven surfaces, bending, stooping, working in confined spaces, and lifting or carrying moderately heavy (20-50 pounds) items and occasionally very heavy (100 pounds or over) items.