Effects of Fire on Human Health and Welfare

Smoke can have negative short- and long-term health effects. High smoke concentrations can cause a serious health risk near homes of people with respiratory illnesses or near health-care facilities. Fire management personnel exposed to high smoke concentrations often suffer eye and respiratory system irritation. Continued exposure to high concentrations of carbon monoxide in the combustion zone can result in impaired alertness and judgment. However, occasional brief exposure of the general public to low concentrations of drift smoke is more a temporary inconvenience than a health problem (Wade and Lundsford 1988).

Over 90 percent of the particulate emissions from prescribed fire are small enough to enter the human respiratory system. These particulates contain hundreds of chemical compounds, some of which are toxic. Repeated, lengthy exposure to relatively low smoke concentrations over many years can contribute to respiratory problems and cancer, but the risk of developing cancer from exposure to prescribed fire has been estimated to be less than one in a million (Wade and Lundsford 1988).

Both theoretical calculations and field studies suggest that prescribed fires are hot enough to destroy any chemical residues from herbicides. Minute quantities of herbicides that may end up in smoke are well within currently accepted air quality standards. Threshold limit values (TLVs) are often used to measure the safety of herbicide residues in smoke. Expected exposure rates of workers to various brown-and-burn combinations have been compared with TLVs. Results showed virtually no potential for harm to workers or the general public (Wade and Lundsford 1988).

Certain plant compounds carried in smoke can have an immediate acute impact on individuals. When noxious plants such as poison ivy burn, the smoke can cause skin rashes that are be much more widespread on the body than those caused by direct contact with the plants. Respiratory systems of individuals that breathe this smoke may be affected (Wade and Lundsford 1988).