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ExxonMobil Chemical Plant (286), Baton Rouge

Releases of Wastewater

LDEQ Accident Number
Accident Date
Point Source(s) Notes Amount of Release

Wastewater treatment tanks
Cause: On September 24, 2005 there were high levels in the Wastewater Treatment Tanks. The levels in these tanks were high because of rain from Hurricane Rite, but have since been returned to manageable levels.

Followup: No

Notes: The tanks did not overfill and no limits were exceeded Amount of wastewater released is unknown.

Cause: They have five tanks that are releasing vapors. One tank is a floating roof tank that is malfunctioning. The other four have some sort of malfunction as well. They are investigating the cause.

Followup: No

Notes: Not sure if any releases will reach RQ

Storage Tank
Advanced Wastewater Treatment Unit
Cause: BRCP Flaring During Shutdown: On September 1, the Baton Rouge Chemical Plant began to safely shutdown operations due to power failures associated with Hurricane Gustav. During shutdown, excess gases were vented to the flare system in order to reduce emissions to the atmosphere. Baton Rouge Turbine Generator NOx steam trip: ExxonMobil experienced difficulty providing NOx suppression steam for our BRTG. Condensate is required to desuperheat the NOx suppression steam prior to using it in the BRTG. The normal condensate supply from operating units to provide desuperheater water is unavailable as these units are down. Temporary demin trailers were used to help provide an interim source of condensate to mitigate the loss of NOx suppression steam, but were unable to continuously supply the condensate for NOx steam to BRTG. Nitrogen blanketing for tanks on vapor recovery: The lack of nitrogen availability has also created a temporary loss of nitrogen blanketing for storage tanks on vapor recovery. Loss of nitrogen blanketing means that air will be pulled into the tank which is unacceptable from a hazard risk standpoint. The tanks without nitrogen blanketing must be blocked away from vapor recovery because it is unsafe to vent oxygen to a fuel gas or flare gas system due to the potential of creating an explosive mixture. Exxon shut down the vapor recovery controls when the site lost nitrogen. Once nitrogen is restored, Exxon will restart vapor recovery systems. Once normal operations are resumed, Exxon will report total excess emissions and duration of vapor recovery outages for affected tanks. Two hatches found open: Two tank hatches were found open after the hurricane was over. These tank hatches were blown open when wind speeds were highest (>90 mph) during the hurricane. Tank hatches must remain closed to prevent emissions; as such, these incidents are considered bypassing of a control device. The estimated emissions from these open tank hatches are below RQ amounts. AWT overflow to Monte Sano Bayou: The separator at the Advanced Wastewater Treatment unit overflowed to the Monte Sano Bayou. The incident occurred when the pumps lost power and could not pump down the level in the separator. Approximately 1300 gallons of untreated wastewater was discharged in to the bayou. Power to the pumps was restored and the level in the separator was pumped down to stop the overflow to the bayou. The composition of the discharged wastewater is unknown at this time due to a disruption in laboratory samples as a result of the hurricane.

Followup: Yes

Notes: BRCP was shutdown due to hurricane Gustav.
1,300.0 gallons

Outfall 001
Cause: Wastewater treatment facilities suffered a loss of biological degradation capability at its Advanced Wastewater Treatment Plant, which was expected to result in LPDES exceedances through Outfall 001 (treated wastewater). Outfall 001 was discharging treated process wastewater into the Mississippi River. The letter from the refinery dated 7/11/11 states that the root cause of the upset condition was still being investigated, but the letter states a belief that inhibition of biomass began mid-June and was exacerbated by cooling system issues in late June. Effluent permit limits were exceeded on three different days - June 29, July 1 , July 4 - for elevated BOD count above the permitted 4,765 lbs BOD/day as indicated by sampling results. On June 29 the plant released 5,408 lbs of BOD/day. On July 1, they released 5,501 lbs BOD/day. On July 4, they released 12,820 lbs BOD/day.

Followup: No

Notes: At the time of the letter dated 7/11/11, the discharge was still occurring, and mitigation and recovery steps implemented included increased storage of influent wastewater, addition of biomass to AWT, restored cooling tower capability to lower wastewater temperature to optimum, and initiation of significant wastewater load reduction measures.
130,000,000.0 gallons

Cause: A notification letter from ExxonMobil (286) references a release of some kind contaminating surface water. No details are provided relating to how the release occurred or what specific contaminants were released.

Followup: No

Notes: ExxonMobil cites in its notification letter that the National Response Center, Baton Rouge USCG, and Water Works Warning Network were notified. The contaminant admittedly released is not provided. A release is admitted but no other details are released in addition to that it was under the reportable quantity.