Reroofing of college buildings is a necessary part of building preservation. During such projects roof tar odors are generated. The following information addresses some of the common concerns associated with roofing projects, and some methods for reducing problems.
No. The sulfur compounds in roofing tar have very low odor thresholds (in the parts per billion range). Smelling the odors does not indicate over exposure.
These can be short term or acute effects of exposure to roof tar odors. The symptoms should resolve within hours after exposure to the odor has stopped. Long term health consequences are not expected for the levels found inside buildings during roofing projects.
There is indirect evidence that exposure to roof tar chemicals may cause birth defects. Laboratory studies of roof tar extracts have shown DNA changes in human fetal cells exposed to asphalt fume extracts. This may be a concern for asphalt workers because of the higher exposure to fumes, but not for building occupants with a much lower exposure.
There is no direct evidence linking the inhalation of roof tar odors to the onset of any cancers. Some epidemiological studies of asphalt workers suggest that they may be at increased risk for skin, lung, stomach, and bladder cancer as well as leukemia. Other studies have been inconclusive. Skin contact with the roof tar has been shown to cause tumors in laboratory animals.
Yes, the roof tar odors can irritate the respiratory tract and aggravate the condition of a person with asthma or other lung conditions. People with asthma should avoid breathing roof tar fumes.
Yes, hydrogen sulfide can be produced from hot roof tar. The levels produced will not be high enough to affect building occupants. Only levels inside an enclosed asphalt kettle may be high enough to pose a serious health threat.