Potable Water Contamination aboard US Naval Ships
In September of 2022, poor maintenance procedures led to sailors aboard US Naval ships drinking and showering in contaminated water. They were exposed to e-coli and jet fuel found in the potable water systems on board the USS Abraham Lincoln and the USS Nimitz. The Navy launched an investigation and recently released official reports which revealed the root cause of the incidents and plants to implement remedial action.
On September 21, 2022 shortly after placing the potable water (PW) tanks in service, Plant Upper Level Starboard Watch informed the Plant Chief Machinery Operator (CMO) the water “tastes weird.” Initially the CMO did not alert the Water Control Watch (WCW) as he believed the taste may have been altered as they left port and began using water from the PW system. Later, the CMO informed the WCW the “tank is bad” without further elaboration. The WCW understood this to mean the free available chlorine measurements were out of specification and sampled the tanks, but placed them back online after sampling.
After continued complaints and many crew members beginning to purchase bottled water from the ship’s store, Medical took bacteriological samples from the PW tanks. The samples required an 18 hour incubation period before results came back positive for coliform and e-coli.
In the Spring of 2022, a hole in the vent header of a potable water (PW) tank was produced due to corrosion. The hole was located 6 inches off the low point in the bilge in the Main Machinery Room and allowed bilge water to flow into a PW tank when levels were high enough.
The bilge water contained sea water, oil, and grease that collected in the bilge during normal operation. The PW tank was put online allowing the contaminated water to spread to other parts of the PW system.
The MP4 Propulsion Plant Piping and Bilge Inspection Program was not tracking this piping as they should have been. Considering the location in the bilge, the vent header was susceptible to corrosion, which led to premature failure in an operational environment with higher than normal bilge levels.
The vent header should have been inspected as “high interest” piping, undergoing frequent inspections. If this was the case the corrosion would likely have been discovered prior to the PW tank being placed online in the fall. There were also many instances of poor communication between crew which deferred the discovery of the potable water contamination.
The USS Nimitz was sailing off the coast of San Diego, CA for a training period prior to deployment. On September 16, 2022 multiple sailors complained of upset stomachs, rashes from showers, and odd smells coming from drinking fountains.
The company discovered the potable water system had been contaminated with jet propellant-5 (JP-5) and the aircraft carrier returned to the pier to begin flushing the water tanks with 1 million gallons of San Diego city water.
Upon further investigation it was revealed the initial contamination occurred during the aircraft carrier’s last deployment in 2020. The ship identified the likely source of JP-5 as back leakage through the main drainage system caused by check valve malfunction. This allowed the bilge to be contaminated with JP-5. The manway access cover for a potable water tank is located in the bilge space and a deteriorated gasket on top of the tank allowed contaminated bilge water to flow in.
Inadequate reporting and miscommunication between crews led to the potable water system being put online.
Following the two separate investigations and reports conducted by the Navy an Aircraft Carrier Potable Water Working Group was established to propose changes to: the potable water maintenance requirements, potable water technical manuals and drawings, shipboard potable water specifications, shipboard water analysis capabilities, shore facility water analysis capabilities, CVN 68 and CVN 78 Class potable water system design, and shipboard and shore pre planned response actions to resolve petroleum product or chemical contamination of the shipboard potable water systems.
This information was collected solely from US Naval Reports. Read the full reports for detailed reporting about the full scope of the incidents: