At approximately 1800 hours on September 23, 2021, a heavy
equipment operator struck a 10” underground pipeline, owned and operated by
NuStar Energy. The pipeline contained anhydrous ammonia. The flow to the
pipeline was shut down remotely at approximately 1900. The pipeline valves on
either side of the breech were manually closed as well, however, approximately
7.36 miles of pipeline exist between the valves. Initial estimates are in
excess of 1,000 lbs. of anhydrous ammonia released, however calculations have
not been conducted. The incident occurred in a gravel quarry operated by
Arkansas Gravel Company and is located between the towns of Hampton and
Harrell, in Calhoun County, Arkansas. Based on air modeling plumes, both towns
have the potential to be affected by the release pending weather conditions.
Arkansas Department of Emergency Management (DEM) evacuated
approximately 60 residents east of Highway 167 (primarily from the south east
side of Hampton). Evacuees are currently sheltered at Hampton High School and
the Hampton First Baptist Church. Arkansas DEM issued a shelter-in-place order
for the area west of 167. The exact number of people affected is unknown.
Arkansas DOT reported the closure of approximately 3.5 miles of Highway 278 due
to the ammonia release. The El Dorado Fire Department was deployed by the
Arkansas DEM to conduct air monitoring. The 61st Civil Support Team (CST) will deploy,
as necessary. NuStar Energy employees are on-site to conduct an investigation
and repair the pipeline.
R6 EPA START contractors and OSC Adam Adams were activated at 2200 on September 23, 2021 to respond, as requested by the State of Arkansas and local responders. Two NRC
reports were issued for this incident (#1317736/1317738). The OSC will use NRC
#1317738 for this incident.