Geological and environmental factors involved in natural gas accidents

Variability in soil mineralogy, texture, and pavement cover are involved in events leading to undetected gas leaks and subsequent explosions in Bowie, Md. and Washington, D.C. These geologic parameters are involved in selectively removing the gas odorant additive t-butyl merceptan as the gas came into contact with the soil near the pipeline breaks. This removal resulted in an accumulation of combustable natural gas without detectable odor. Soil samples from drill holes and near surface sites were utilized to map soil type, texture, and mineralogy. Residual methane content of the samples was also measured. The data from two dissimilar sites indicates that finegrained soil enriched in montmorillonite preferentially removes the odorant.