CDC Report Describes Fishing Crews’ Exposures to Sea-Disposed Chemical Warfare Munitions

Commercial fishing vessels dredging for shellfish may inadvertently recover unexploded chemical warfare munitions (CWMs), creating risks for severe worker injury and food contamination, according to CDC’s March 5 Morbidity and Mortality Weekly Report (MMWR). An estimated 17,000 tons of CWMs dating from World Wars I and II, including mustard gas, were disposed of in Atlantic waters before 1970, CDC explains. The MMWR describes three incidents of unintentional CWM recovery off the coast of New Jersey in 2016, 2017, and 2023. All cases led to workers receiving injuries consistent with mustard agent exposure and the destruction of contaminated seafood product.

In August 2016, workers discovered a ruptured CWM on the conveyor belt of a fishing boat off Atlantic City. The crewmember who threw the munition overboard suffered from second-degree burns and large, fluid-filled vesicles on their arms, requiring hospitalization, skin grafting, and physical therapy. Communication delays resulted in some contaminated clams entering food production, leading to the recall of 192 cases of clam chowder base. An additional 704 cases of clams were destroyed.

In August 2017, a crate containing 20 cannisters of mustard gas broke open on the sorting belt of a ship off Long Branch, exposing three crewmembers to the toxic agent. The cannisters were thrown overboard using a magnet. A crewmember who disentangled a CWM from a fishing net received second-degree burns to the forearms. The other two workers were uninjured. The New Jersey Department of Health was notified and about 5,300 bushels of clams were embargoed, sanitized, destroyed, and disposed of in a landfill.

In October 2023, two crewmembers were exposed to the contents of a leaking CWM off Cape May. One worker threw the CWM overboard and required overnight emergency treatment for respiratory distress and second-degree burns to their arms and neck. The other worker was in the boat’s enclosed wheelhouse and reported a burning sensation on their face but did not require medical treatment. A holiday weekend prevented the immediate notification of appropriate officials, delaying the destruction of 32 bushels of contaminated clams.

CDC notes that ocean drift, storms, and offshore industrial operations may cause sea-disposed CMWs to drift far from their original dump sites. Although the London Convention of 1972 banned marine dumping of CMWs, U.S. law does not require the active recovery or destruction of CMWs that have been underwater for so long they are thought to have degraded to the point they are no longer considered military weapons. The safest option for fishing crews is to throw dredged CMWs overboard, but this may lead to future recovery and exposure.

Responses to dredged CMWs are complicated and time-consuming, involving the Coast Guard, the Food and Drug Administration, state agencies, and fish and seafood operations, CDC’s report explains. The authors conclude that robust communication between these entities may reduce worker harm and foodborne illnesses from sea-disposed CMWs.

CDC recommends applying the hierarchy of controls to prevent CWM exposures. First, commercial fishing vessels should avoid documented dumping sites. Fishing operations should use engineering controls, including containment and magnet-assisted sorting of dredged material. They should also implement administrative controls, such as the 3Rs of Explosive Safety—recognize, retreat, and report—a procedure developed by the Army for civilians who encounter unexploded ordinance. Finally, crewmembers should receive adequate personal protective equipment and training to safely handle recovered CWMs.

The March 5 MMWR provides more information on exposure to chemical munitions during commercial fishing operations. CDC’s website offers guidance on the recovery of sea-disposed chemical warfare material.