Background:

EPA responded to the incident between March 15-20 to ensure the Blackcat Oil Company was taking the appropriate actions to clean up oil from Little Cow Creek, to prevent oil from migrating further along the waterway, and to prevent additional oil from making entry into Little Cow Creek. While on site between March 15-20, EPA determined Blackcat Oil Company was undertaking an appropriate response. EPA remotely received daily updates from Blackcat Oil Company between March 21-April 5 to ensure Blackcat Oil Company continued to undertake an appropriate response. On April 5, Blackcat Oil Company informed EPA they had completed decommissioning the tank battery, transporting all contaminated soils from the site to a disposal facility, and backfilling the excavated area with clean soils. EPA returned to the site on April 10 to conduct a site inspection to verify that these activities were completed and to verify that no free-standing oil remained in Little Cow Creek.

April 10, 2024 Site Inspection Summary:

EPA observed that Blackcat Oil Company had completed decommissioning the tank battery and removing piping from site, although an oil water separator remained at the site. According to Blackcat Oil Company, the oil water separator will be removed from the site on April 15. EPA observed that the spill source area had been excavated and filled with new, outsourced soil. EPA walked the spill pathway along Little Cow Creek and observed a minor cloudy white sheen in a few areas however, no free-standing recoverable crude oil was observed throughout the entirety of the creek or along the creek banks. EPA determined that Blackcat Oil Company had recovered as much possible oil from Little Cow Creek and had mitigated the threat of any additional oil from making entry into Little Cow Creek.

Planned Activities:

There are no further planned EPA response activities. The Oklahoma Corporation Commission will continue overseeing Blackcat Oil Company's remediation efforts until contaminant levels in surface waters and soils are below state regulatory standards.

March 25 Update on Blackcat Oil Company's (Responsible Party or RP) Clean-Up and Containment Efforts:

EPA observed that the RP recovered most of the free-standing oil in Little Cow Creek and had completed low pressure washing Little Cow Creek's banks. Low pressure washing of the Little Cow Creek's banks was conducted to displace and recover the residual oil and debris which had adhered to the creek's banks. The RP recovered around 175 barrels of oil/water mixture from Little Cow Creek and 10% of the recovered oil/water mixture is estimated to be oil. During the week of March 18, the RP also began decommissioning the tank battery, removing piping from site, and excavating impacted soils near the spill source area. 

Planned activities:

During the week of March 25, the RP will continue to decommission the tank battery on-site as well as excavate oil contaminated soils near the spill source area. EPA demobilized from the Site on March 20 and will continue to receive daily updates from the RP until impacted soils near the spill source area are excavated and transported off-site for disposal. Once soil excavation is completed, EPA will return to the site to conduct a final inspection to verify that contaminated soils have been excavated and transported off-site for disposal and that no free-standing oil remains in Little Cow Creek.

Key issues:

Minimal amounts of oil continue to leach from contaminated soils near the spill source area into Little Cow Creek. The RP has deployed absorbent and containment boom in the area where oil makes entry into Little Cow Creek as a containment measure and is actively recovering oil that accumulates in the containment area. 3 underflow dams remain downstream of the containment area as a precautionary measure in case oil migrates past the containment area.

March 18 Update on Blackcat Oil Company's (Responsible Party or RP) Clean-Up and Containment Efforts:

The RP has recovered the majority of the free standing oil in Little Cow Creek.  As of March 18, the RP has recovered around 175 barrels of oil/water mixture from Little Cow Creek. Around 10% of the recovered oil/water mixture is oil. The RP also began low pressure washing Little Cow Creek's banks to displace oil which has adhered to the creek banks and is recovering the residual oil and debris which is coming off the banks. The RP and their contractors also began decommissioning the tank battery and removing piping from site. The RP has also began began excavating and remediating soils near the spill source area adjacent to the tank farms.

Planned activities:

The RP will continue to low pressure wash Little Cow Creek's banks and collect residual oil and debris.  A 3rd underflow dam will be constructed on Little Cow Creek on the morning of March 19. Underflow dams are used to trap oil so it can be recovered while simultaneously allowing water to move through the creek. The RP will also continue to decommission the tank battery on-site as well as excavate and remediate oil contaminated soils near the spill source area. EPA will continue to provide oversight of the RP's clean-up efforts until the Little Cow Creek bank washing efforts are completed and the oil contaminated soils near the spill source area are removed from the site. 

Key issues:

Rain is forecasted in Perry, OK on March 21. Minor amounts of oil are still contained near the spill source area and in the banks of Little Cow Creek. The RP has already constructed 2 underflow dams to keep oil contained in Little Cow Creek and will construct a 3rd underflow on the morning of March 19 to ensure oil remains contained in Little Cow Creek through the rain event and doesn't migrate any further.

Status of the Blackcat Oil Company's (Responsible Party or RP) Clean-Up and Containment Efforts between March 15-17:

Between March 15 and 17, the RP deployed absorbent boom in several locations along Little Cow Creek and constructed two underflow dams in Little Cow Creek in an effort to keep oil from migrating further along the creek.  EPA's technical assistance contractor observed a thin rainbow/metallic sheen as far as 1000 feet downstream from where oil entered Little Cow Creek however, only around 200 feet of Little Cow Creek contained significant amounts of free standing oil. EPA's technical assistance contractor has not observed any sheen in Cow Creek. The RP has began recovering free standing oil in Little Cow Creek with vacuum trucks. According to the RP, they have recovered around 160 barrels of oily water mixture from Little Cow Creek.

Planned activities:

The RP will continue oil recovery operations through the week of March 18 and anticipates recovering all free standing oil in Little Cow Creek by Thursday March 21. Once the RP has collected all free standing oil from Little Cow Creek, they will begin low pressure washing Little Cow Creek's banks with water and will continue collecting oily-water fluids with vacuum trucks. The RP will also address contaminated soils in the area that leads into Little Cow Creek once they've recovered all free standing oil in Little Cow Creek.

Key issues:

Rain is forecasted in Perry, OK on Thursday March 21. EPA has requested the RP develop a contingency plan to ensure a rain event does not cause oil to migrate further in impacted waterways. The RP will provide EPA a contingency plan by the end of the day on Monday March 18.