ST Services Nustar Energy LP

The Site is located at the 5400 block on the west side of NW Fruit Valley Road. NuStar Terminals Operations Partnership L.P (NuStar) owns the property. The property is a tank farm with seven large aboveground storage tanks used to store petroleum products. In 2003, NuStar acquired the facility from Cenex Harvest States Cooperatives.

In 2001, Ecology learned about a gasoline spill, apparently due to equipment failure at an underground storage tank. Investigations showed that gasoline, diesel, naphthalene and BTEX (benzene, toluene, ethylbenzene and xylenes) contaminated soil and groundwater that needs to be addressed under the state’s cleanup law, the Model Toxics Control Act (MTCA). Contamination needs to be cleaned up in three areas at the Site. 

Details on several of the contaminants:

Benzene: Benzene is a colorless liquid that can evaporate quickly in air and can dissolve in water. It is one of the top 20 chemicals produced in the United States, and is also found naturally in crude oil. Industrial processes are the main source of benzene in the environment. For more information, visit https://wwwn.cdc.gov/TSP/substances/ToxSubstance.aspx?toxid=14

Toluene: Toluene occurs naturally in crude oil but is also created during the fuel production process. It is used to make a wide range of products including paints, adhesives and paint thinners. For more information, visit https://wwwn.cdc.gov/TSP/substances/ToxSubstance.aspx?toxid=29

Xylene:  Xylene is found naturally in petroleum and coal tar but is also produced from petroleum. It is one of the top 30 chemicals produced in the United States and is often used as a solvent in various industries. In gasoline, it is found in very small amounts. For more information, visit https://wwwn.cdc.gov/TSP/substances/ToxSubstance.aspx?toxid=53

Naphthalene:  Naphthalene is produced by burning tobacco or wood. It is used commercially to create plastics and in homes to repel moths (moth; balls). Naphthalene can be found in petroleum and coal. For more information, visit https://wwwn.cdc.gov/TSP/substances/ToxSubstance.aspx?toxid=43

For information on the risks of other contaminants present at the site, please visit the ATSDR database. 

Possible pathways of exposure: 

Groundwater: At the Site, groundwater is generally between 14 and 32 feet below the ground surface. The area of contamination in the groundwater is called a plume. There are three isolated groundwater plumes. Clark Public Utilities (CPU) is developing a drinking water supply well field located approximately 1,000 feet north of the Site that will supply water to the area. This supply well is anticipated to be online as early as 2023. The proposed remedy is anticipated to contain and treat the plumes and prevent them from migrating toward the CPU drinking water supply well.

Vapor intrusion: Vapor intrusion is not a concern at the Site because there are no structures in the vicinity of the contamination. Vapor intrusion is not anticipated to be a pathway since the property is currently developed as a tank farm with existing aboveground storage tanks and an associated piping system.  There are no structures on site where vapors could be a pathway to impact human health.

Soil: Petroleum contamination extends from 6 to 12 feet below ground near the truck loading area and from 4 to 21 feet below ground in the two plume areas on the western portion of the property.