Due to their profession's hazardous characteristics, sewage divers, for example, are exposed to highly polluted waters, sewage contaminated with biological, chemical, and physical waste. They have to be very cautious and wear protective gear because even a minor scratch could become a significant source of infection. They take care of sewage blockages to ensure that effluent does not return into the streets and houses. The occupation is so dangerous that it is prohibited in many nations.