Final answer:
Workers exposed to poor air quality from dust, smoke, or fumes are provided with protective respirators to prevent occupational diseases like hypersensitivity pneumonitis, according to OSHA regulations.
Step-by-step explanation:
Protective respirators are provided to workers who operate in environments with poor air quality due to the presence of dust, smoke, or fumes. Option D captures this scenario correctly. This is because when working in areas with hazardous substances in the air, respiratory protection is essential to prevent health issues. Notably, hypersensitivity pneumonitis is an occupational disease that can arise from prolonged exposure to allergens such as dust and molds which are found in places like bird rearing facilities or cheese processing plants. Employers have the responsibility, under Occupational Safety and Health Administration (OSHA) guidelines, to ensure their workers are safe by providing the necessary protective equipment like respirators after attempting to mitigate hazards at the source.