DEP’s Northwest Regional Office has been in contact with United Refining Company throughout the incident.
On Tuesday, April 12th, United Refining accessed the tank to begin removal of the remaining liquid from the bottom of the tank.
United Refining completed the removal of the remaining liquid from the tank on Thursday, April 14th.
Once the remaining liquid was removed from the tank, the incident was no longer considered to have any potential environmental impacts and the Community Wide Air Quality Monitoring network was shut down.
DEP did not receive any odor complaints after the initial days of the incident.
A multi-layered sampling plan was developed shortly after the start of the incident and included the establishment of a Community-Wide Monitoring Network, the Passive Fenceline Monitoring Network required for all refineries, DEP Complaint Response Monitoring and SUMMA Canister Sampling.
Community-Wide Monitoring Network:
At DEP’s request, United Refining installed a Community-Wide Monitoring Network which consisted of six sampling locations placed throughout the City of Warren. Each monitor provided continuous sampling for hydrogen sulfide, volatile organic compounds, oxygen, carbon monoxide and lower explosive limit levels.
DEP was provided remote access to the real time data throughout the incident and would have received alerts from the system had any action levels been exceeded.
These monitors did not detect an emission impacts requiring DEP follow-up/investigation during the entire sampling period.
Passive Fenceline Monitoring Network:
United Refining is required by federal regulation and its operating permit to implement a passive fenceline monitoring network for benzene. This passive benzene monitoring continued to be conducted throughout the incident.
Each sampling period lasts for two weeks and the data from the passive sampling was immediately provided to DEP upon receipt.
On March 10, 2022, United Refining transmitted the results of the Benzene sampling for the two week period from February 15, 2022 through March 1, 2022 which included the start of the incident.
United Refining included the following statement in its transmittal of the report to DEP: “The Benzene Fence line tube concentrations around the tank were higher than our normal readings. The max being 25 µg/m3 which converted for Benzene equates to 7.57 ppb. Keep in mind these fence line monitoring locations are located inside the fence line or on the fence line not in the community. The action level for these measurements are (ΔC) > 9 µg/m3 for an annual average (40 CFR 63 Subpart CC 63.658 (f)(3)). United’s annual average after this period is 1.78 µg/m3.”
On March 25, 2022, United Refining transmitted the results of the Benzene sampling for the two week period from March 1, 2022 to March 15, 2022.
United Refining included the following statement in its transmittal of the report to DEP: “The sample locations around the tank still shows and elevated reading but much reduced compared to the last cycle. The max reading being 10 µg/m3 which converted to Benzene ppb equates to 3.03 ppb of Benzene. Keep in mind these fence line monitoring locations are located inside the fence line or on the fence line not in the community. The action level for these measurements is (ΔC) > 9 µg/m3 for an annual average (40 CFR 63 Subpart CC 63.658 (f)(3)). United’s annual average after this period is 2.11 µg/m3.”
Neither of the reports received to date for the passive benzene monitoring network indicated exceedances of the short or long term action levels identified in the Sampling Plan.
DEP Complaint Response Monitoring
DEP did not receive any complaints after sampling plan was developed, therefore, the sampling protocols for complaint response monitoring were not utilized.
SUMMA Canister Sampling:
DEP conducted two sets of 12-hour samples at three locations in the City of Warren on February 25, 2022 and February 26, 2022.
All of the results showed benzene sample results at or below 0.190 parts per billion which was well below DEP’s action level of 9 bbp for the incident.
Using an abundance of caution, DEP did conduct additional SUMMA testing during the period in which United opened the tank to remove the remaining liquid from the tank. Those test results have not been received.
For more information, visit DEP’s Northwest Regional Office United Refining Company webpage.
(Photo: United Refinery, Warren, Warren Times Observer.)
[Posted: April 19, 2022] PA Environment Digest
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