Some 1,400 gallons of heavy fuel oil was discharged into the Mississippi River from the 45,683 dwt chemical tanker Iver Exporter on April 23, according to the US Coast Guard.
Initial reports suggested that up to 2,600 gallons of oil was discharged into the river near Norco, Louisiana.
The incident, which occurred near mile marker 126 on the lower Mississippi River, did not affect the waterway traffic.
USCG informed that the source of the discharge is secured and the 2000-built tanker, owned by the Netherlands-based Iver Ships, is currently moored at the Shell Norco Manufacturing Complex.
Overflights, on-water and shoreline assessments were conducted and shoreline impact was identified from mile marker 126 to 122. At present, 40 people and six vessels are deployed in response to the incident.
Air monitoring is being conducted along the impacted region, and air quality remains safe, the USCG said, adding that there are no reports of injuries or wildlife impacts due to the incident.
The cause of the oil discharge is still under investigation.
This is the second oil spill which occurred in in the lower Mississippi River during April.
Following an allision with a pier, the Singapore-flagged Pac Antares started leaking diesel fuel. The oil spill was reported in the morning hours of April 12 close to the river’s mile marker 100 near New Orleans.