U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

NuStar NH3 Pipeline

Site Contact:
Adam Adams
On-Scene Coordinator


Site Location:
2301 Calhoun 26
Hampton, AR 71744
NRC#: 1317738

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.

For additional information, visit the Notices section.