Factors Affecting Hydrocarbon Vapor Transport From Leaking Storage Tanks to Buildings in Texas
Date
1998-05
Authors
Chandler, Christine W.
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Abstract
As of January 1998, 152,000 underground storage tanks containing mainly common petroleum fuels such as gasoline, diesel fuel, kerosene, jet fuel, and aviation gasoline were located at 63,400 facilities in Texas. Since 1986, the Texas Natural Resource Conservation Commission (TNRCC) has documented more than 20,000 known leaking petroleum storage tank (LPST) sites in the state. The contamination caused by these releases may be limited to minor soil contamination or, in more serious cases, it may migrate to the groundwater and travel to drinking water wells. One of the most serious hazards of leaking storage tanks, vapor impacts to buildings, often requires emergency measures to prevent potential explosions. Fortunately, vapor impacts occur in only a small proportion of the sites with petroleum storage tanks. The occurrence of vapor impacts appears to be a result of a combination of factors involving the depth to groundwater, soil type, precipitation, type of petroleum product, and the presence of phase-separated hydrocarbons (also termed free product). The most common vapor impact occurs from a release of gasoline into clayey soil that results in phase-separated hydrocarbons (PSH) on shallow groundwater. Sites with a shallow, impermeable rock layer are particularly susceptible to vapor migration. Underground utility lines in contact with, or near, the groundwater allow for easy transport of the vapors into nearby buildings. Precipitation events that release adsorbed hydrocarbons by wetting the soils appear to initiate most vapor impacts. The results of this study will be used to identify those leaking storage tank sites which may result in a vapor impact so that monitoring and corrective measures can be initiated as necessary.
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Keywords
volatile organic compounds, hazardous wastes, petroleum products
Citation
Chandler, C.W. (1998). Factors affecting hydrocarbon vapor transport from leaking storage tanks to buildings in Texas (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.