309 American Circle, El Dorado, Arkansas 71730

A tractor trailer containing approximately 1,249 (5) gallon containers of pool treatment solids, granular chlorine and granular stabilizer, had a reaction from unknown causes, and created a chlorine gas plume. The tractor trailer was located in the Clean Harbors 10-day holding lot adjacent to the main Incineration facility. The gas plume migrated off the site and into an area where a federal prison and other governmental offices were located. Runoff water was created by the Clean Harbor fire brigade's attempt to knock the vapors down migrated into a local storm sewer. The local fire department installed a temporary evacuation/shelter in place downwind of the facility stretching up to 5 miles. The evacuation/shelter in place order was lifted at 2035 hours. Due to the potential impact of the chlorine gas plume, OSC Peterson dispatched OSC Brescia and START-3 to conduct air monitoring activities and to conduct an assessment of the incident.

On 12/18/2012 at 1630, Clean Harbors discovered one of their tractor trailer's carrying pool chemicals had undergone a reaction due to unknown causes and was creating a gas plume. Clean Harbors contacted the generator/shipper of the waste to verify the trailer's contents, and then contacted the National Response Center (NRC) to report the incident. The Clean Harbor fire brigade responded to the incident and began flooding the trailer with water in an attempt to cool the waste and to prevent additional gas fumes from being released. The El Dorado Fire Department and representatives of ADEQ were dispatched to the scene. EPA Phone Duty Officer( EPA PDO) Petersen attempted to contact  Clean Harbors, but was unsuccessful in making contact to gather more information. At 1830 hours, EPA Phone Duty Officer Peterson dispatched EPA OSC Brescia to the scene. OSC Brescia dispatched START-3 to the site to conduct air monitoring and assessment activities.

On 12/19/2012, at approximately 0030, EPA OSC Brescia arrived on scene and met with the facility engineer. At approximately 0130 EPA START arrived on scene.  The facility engineer conducted a site walk with OSC Brescia and EPA START. At the time of the site walk, the reaction had ceased with a residual gas plume still visible. Fire fighting water had gathered in a local storm sewer drain system.

The reaction occurred at approximately 1600 hours on 12/18/12 and was mitigated by on-site fire personnel by 1900 hours on 12/18/12. The reaction originated inside of a tractor trailer carrying plastic pales of Dichloroisocyanurate and Trichloroisocyanuric Acid. The tractor trailer was located at the facility’s 10-day storage yard, and the incident created a plume of chlorine gas that drifted off site and over a nearby prison and a corridor of Highway 167. In concurrence with the local fire department, the Sherriff’s Department evacuated 163 inmates and all employees from a prison located across the street, and enacted a shelter-in-place of all residential neighborhoods 5 miles downwind (north) of the incident. Clean Harbor representatives informed OSC Brescia that a drainage ditch which was located along the northern border of the facility was blocked off and the run-off water had been contained within the ditch. Clean Harbors had utilized vacuum trucks to remove the run-off water from the main drainage area and was storing the run-off water on-site in frac tanks pending disposal. OSC Brescia asked Clean Harbors if they conducted air monitoring specific to chlorine during the incident. Clean Harbor’s representative informed OSC Brescia that no real-time monitoring instruments designed to detect chorine were available during the event on site to monitor for off-site impacts. Clean Harbors personnel utilized Draeger tubes around the incident location to detect chlorine. Clean Harbors informed OSC Brescia that no detection for chlorine was found utilzing the tubes. At approximately 0100, CTEH arrived on-site to perform  air monitoring for Clean Harbors both at the fence line and in residential areas located downwind. CTEH was contracted by Clean Harbors to perform air monitoring for chlorine and for particulates. Clean Harbors collected water samples of the run-off water at the main drainage area to be analyzed for chlorides. During the site walk, EPA START conducted air monitoring for chlorine next to the trailer and at the facility fence line downwind of the incident. Air monitoring results indicated detections of chlorine below 0.5 ppm adjacent to the trailer and no detections of chlorine at the fence line. The reaction had ceased and residual gas was emanating from the trailer. All water flushing activities had ceased and Clean Harbors had stationed a fire brigade at the trailer until cleanup operations could begin later that morning. After the site walk, OSC Brescia determined that the immediate health threat had been mitigated and informed Clean Harbors that he and EPA START would return later that morning to conduct an assessment of the run-off water and to assess the prison facility prior to rentry of prison occupants. OSC Brescia also informed Clean Harbors to notify him if additional reactions occurred and if a new gas plume was created releasing additional chlorine gas. OSC Brescia and EPA START demobilized from the scene.

On 12/19/12 at approximately 0800, EPA OSC Brescia and EPA START mobilized to the scene and met with Clean Harbor representatives and CTEH. Clean Harbors informed OSC Brescia that no further reactions had occurred. CTEH informed OSC Brescia that no chlorine detections were observed during their morning monitoring activities. OSC Brescia, EPA START, and CTEH conducted an air monitoring sweep at the prison location and found no detections of chlorine. OSC Brescia in concurrence with Clean Harbors and CTEH informed the detention center manager that his facility was safe to reoccupy.  Clean Harbors began cleanup activities at the incident location including vacuuming any residual run-off water from the main drainage area. Clean Harbors utilized a track hoe to remove the remaining contents within the tractor trailer and staged the contents on-site in a poly-lined staging area pending on-site disposal. Pooled areas of water that had been removed via vacuum trucks during the emergency phase of the incident  were stored on-site in frac tanks pending on-site disposal. Clean Harbors will be taking soil samples at the incident location to determine if any excavation of soil is needed.

OSC Brescia and EPA START followed the run-off water from the main drainage area to the outfall location at a nearby creek. It was determined that the run-off water did breach the main drainage area and migrated off site into a nearby creek. EPA OSC Brescia contacted EPA ERT to discuss the run-off water issue and was informed that any water that contained a pH of 6 or below should be removed from the ditch due to its effect on biologicals. EPA START and Clean Harbors representatives conducted pH testing at multiple locations along the path of the run-off water and determined that the run-off water was above a pH of 6 and ranged between 6.4 and 7.3.  In consultation with EPA ERT, due to the short life of chlorine in water, OSC Brescia determined that it was not necessary to remove the residual run-off water in the ditch line area. Clean Harbors informed OSC Brescia that their previous water sample analysis of the run-off water indicated no detection for oxidizers and low levels for chlorides. OSC Brescia requested that Clean Harbors provide copies of their air monitoring results, water analysis and any waste manifests generated from their cleanup activities. Clean Harbors agreed to forward the information as it became available.

OSC Brescia and EPA START requested information on any potential health effects reported to the El Dorado Fire Department. The El Dorado Fire Department was unaware of any patients admitted to the local hospital due to the incident.

Clean Harbors will forward all requested cleanup documentation to OSC Brescia.