“For years, and through an historically long deployment during the most disruptive phase of the COVID pandemic, the aircraft carrier Nimitz was hauling around polluted water in its potable water tanks, and more than a third of those 26 tanks were out of commission.”
Harder than any discussion of the viability of the flattop falls that line. Once the fundamental system, upon which all the watches, meals, showers and medical reactions rely, collapses, the combat strength of a carrier is secondary to a greater immediate issue, to maintain thousands of people healthy and working during transit.
A case study of USS Nimitz (CVN-68) and USS Abraham Lincoln (CVN-72) explains two different contaminating and a common weakness: the old age shipboard plumbing combined with maintenance and report breaches that permitted menace to lurk above ground. JP-5 jet fuel found its way into the drinking water at Nimitz and 11 sailors reported symptoms of the exposure. On Lincoln, a corrosion-induced piping meltdown enabled bilge contamination and several tanks were found positive of E. coli, a bacteria that causes acute gastrointestinal infection despite non-confirmed cases being detected shipwide.
The Nimitz incident illustrates how one of the engineering departments can take a risk without knowing that it is a hazard. One day during a day of maintenance, the crew asked assistance in cleaning eight out-of-service potable tanks which were suspected of being contaminated by the sea water, only one was repaired, “due to limited time and resources available.” The vessel then shifted to self-help planning whereby the tank contents were pumped using installed potable piping and pumps. The reason it was a critical miss was provenance: “did not know or consider the possibility that the tank might contain contaminants other than seawater.” The source was later linked to a faulty gasket that had enabled leakage of fuel in a tank during a previous deployment making an internal cleanup a systemwide contamination.
The first error was not the limit of the human factor. It spread to response preparedness. The described investigation characterized an organization with no onboard tools or playbook to quickly characterize fuel contamination in potable lines, resulting in the need to rely on off-ship testing and ad hoc response efforts. Late sampling indicated that hydrocarbons were found with a level of as much as 4.9 parts per million and compared to a Navy limit of 0.266 parts per million. The system was so dirty that the only way to clean it was to flush it over a long period to dislodge all the dirt in over one million gallons of shore water, and it should be borne in mind that to clean up the internal utilities of a carrier is more akin to “rehabilitation” by industrial means than to ordinary maintenance.
The case of Lincoln is an account of a slower-paced failure with more obvious cautionary flashing lights. There was a hole in a vent header pipe, six inches above the bilge deck that was opened so that bilge water could enter the boat when the levels were high enough to allow it to enter. When the sailors complained that the water had a funny flavor a premature ruling that the complaint was not to be raised assisted in procrastination. Four failed opportunities where watch standers could have detected and isolated the contamination before it escalated were later quoted by investigators.
The longer arc mattered, too. Lincoln had previously test-positive five potable tanks in 2022 and investigators noted that the ship allowed this deviation to normalize without clearly bounding the problem or taking corrective action. What ensued was the shipboard culture in which an abnormal indicator added to the background noise.
There is also another type of uncertainty that is not brought by bacteria in fuel in water. According to the Agency of Toxic Substances and Disease Registry, these fuels consist of hundreds of hydrocarbon compounds and that possible effects will be determined by the dose, duration, and route of exposure. It is precisely such variability that makes procedures, detection ability, and disciplined record keeping as significant as the state of hardware condition on large-deck vessels.
The investigations in both instances were focused on backlog of maintenance, corroded parts and lack of full compliance with the basis of sampling and watchstandings. The engineering lesson is rather plain: supercarriers are not airfields on the sea; they are in themselves municipalities, and potable water is one of the few failures that can put a ship out of business without the enemy showing up anywhere on the horizon.
