Sunoco Pipeline, LP (Sunoco) is pleased to inform the residents and neighbors of the SilverHawk neighborhood that our initial surface wipe samples and soil testing results indicate that any residual hydrocarbons are well below health-based screening values, which means there are no concerns for residents related to any health impacts for your families or your pets. These tests are in addition to continuous air monitoring that has been conducted in real-time each day since May 11th, which has also shown that the air quality in the SilverHawk neighborhood is safe and consistently within established air quality standards.
Sunoco contracted scientists from CTEH® to collect surface wipe samples and soil samples from the SilverHawk neighborhood prior to Sunoco’s performance of any cleaning at the homes included in the attached results. The goal of this sampling was to determine whether petroleum hydrocarbons were present prior to any cleaning performed by Sunoco on residential surfaces or shallow soil at levels that would present a health concern. Scientists from CTEH® continue to collect wipe samples and soil samples from the Silverhawk Neighborhood after Sunoco’s cleaning, and those results will be released when they are received.
Sampling was conducted according to plans reviewed by the Oklahoma Corporation Commission (OCC). Shallow soil samples were collected approximately three days after the initial crude oil release from the front and back yards of residential properties where visible impact was reported. Wipe samples were also collected from surfaces at these residences. The samples were sent to Gulf Coast Analytical Laboratories, L.L.C., an Oklahoma‐certified laboratory, for testing. The samples were tested for petroleum hydrocarbons found in the crude oil that was released during the Sunoco pipeline incident.
For wipe sampling comparison, CTEH® derived a health‐based surface screening level of 1,400 ug/100 cm2, using methods established by the United States Environmental Protection Agency (USEPA) during the cleanup of the World Trade Center collapse, and compared them to the surface wipe sampling results. The state of Oklahoma has not established a screening method for surface wipe samples, therefore the USEPA method is the most applicable existing standard. Soil sampling results were compared to Oklahoma Corporation Commission (OCC) Tier 1 and the Department of Environmental Quality (DEQ) Tier 1 screening concentrations for cleanup of petroleum impacted residential soils (2,600 mg/kg). These Tier 1 screening concentrations are specifically established to protect human health.
The results of the sampling are summarized in Attachment 1. The test results for the wipe and soil samples taken prior to any cleanup activity do not indicate petroleum hydrocarbons were present on residential surfaces or in soil samples at levels that would present a health concern. The low-level estimated detections are well below the above-mentioned health-based screening values, and therefore do not indicate any risk to the health of residents prior to the cleaning of homes.
Separately, CTEH® has been conducting continuous air monitoring (i.e., 24-hours per day) of the SilverHawk Neighborhood since May 11th. Real-time air monitoring has been conducted using hand-held monitoring instruments to document and quantify the potential airborne release of oil-associated compounds measured as general volatile organic compounds (VOCs) and benzene.
The air monitoring data are summarized in Attachments 2 and 3. As of Friday, May 18th, no benzene has been detected in the residential neighborhood. There were infrequent low concentration detections of VOCs, which may not be related to the oil release as there are many sources of VOCs in the environment (such as from cars, lawn mowers, construction materials, and natural sources like trees). Even those detected VOCs were not at levels that posed concern for human health effects.
CTEH® is the nation’s leader in providing innovative solutions in the field of toxicology and environmental health related to environmental chemical releases. With more than twenty years of experience responding to 1,000’s of Hazmat incidents across North America, CTEH® employs board-certified toxicologists, industrial hygienists, and safety professionals to better help protect individuals, communities, and the environment itself.