Breathing raw sewage fumes can be both unpleasant and physiologically damaging. Raw sewage produces a melee of gaseous compounds. Common colorless gases encountered in sewage systems include hydrogen sulfide, carbon dioxide, methane and ammonia. High levels of these gases become toxic, and high concentrations of methane and carbon dioxide, in particular, displace oxygen in the air. Additionally, industrial solvents and biological contaminants in sewage may become airborne and cause adverse health effects.
Problems Posed by Gases
Both hydrogen sulfide and ammonia have odors that forewarn their presence. Methane and carbon dioxide do not. As methane and carbon dioxide replace the oxygen content in the air surrounding raw sewage, normal levels of nitrogen increase as well. For every 5 percent of methane present, 1 percent of oxygen is displaced. Normal air contains 21 percent oxygen and 78 percent nitrogen. Decreasing oxygen concentrations by displacement with other gases can lead to asphyxiation and tissue damage.
Industrial Toxin Fumes
Consumer and industrial products poured down drains end up in raw sewage. Solvents, flame retardants, pesticides, cleaning products and volatile organic compounds mixed together in raw sewage may instigate toxic gas formation. Vapors from bleach, a common cleaning product found in raw sewage, can irritate the respiratory system. Also, as surfactants such as alkylbenzene sulfonate, alcohol ethoxylate and alcohol ether sulfate -- chemicals from the cosmetic and detergent industries and laundry or car-washing services -- become airborne, they can irritate mucous membranes.
Airborne Biological Contaminants
Volatilization is the gaseous loss of a substance to the atmosphere. Agitation of raw sewage can cause volatilization of biological contaminants in sewage, although this type of microbial suspension is short-lived. Breathing suspended microbial contaminants may infect a person with bacteria, fungi, parasites or viruses. Bacteria and parasites often cause diarrhea, fever, cramps and vomiting. Symptoms of fungal infections include allergic reactions and lung infections. Viral symptoms vary.
Other Physiological Effects
The effects of breathing raw sewage gas can be wide-ranging. Subtle signs of gas exposure may include headaches, coughing, nausea and irritation of mucous membranes, which can occur when raw sewage backs up into a home or business. People who work with raw sewage on a daily basis may encounter higher exposure to fumes. These individuals may experience headaches, dizziness, fatigue, eye irritation and shortness of breath.
Several research studies have looked at the effects of raw sewage on people who work in the field of sewage treatment. According to a 2014 article published in the Journal of Clinical and Diagnostic Research, occupational exposure to sewage dust, fumes, gases and bio-aerosols contributed to oxidative stress, which was one of the mechanisms leading to obstructive impairment of lung function in the workers. Also, a 2011 study in the International Journal of Occupational and Environmental Medicine states that workers at wastewater treatment plants are at high risk for developing infections.