Mystery Spill Returns to San Juan Harbor

Port of San Juan mystery spill
Courtesy U.S. Coast Guard

Published May 1, 2024 7:38 PM by The Maritime Executive

The U.S. Coast Guard is working to clean up a mystery spill at the port of San Juan, Puerto Rico. According to Sector San Juan, a recurring discharge of heavy oil is seeping out of the storm drain system into the water, and experts are trying to trace it back to its source. In the meantime, thanks to funding from the Oil Spill Liability Trust Fund, a contractor is keeping the contamination contained and pulling oil out of the water. So far, about 1,770 gallons of waste have been recovered, including 17 drums of absorbent materials. 

"The discharged oil is being contained and recovered," said Lt. Cmdr. Ray Lopez, Sector San Juan Incident Management Division Chief. "We suspect this spill may be tied to an unidentified inactive historical source that for years has resulted in a series of mystery spills along the Old San Juan waterfront."

It is not the first time that an oil seep like this has leaked into San Juan's harbor. Three years ago, another release of a substance that looked like Bunker C occurred at Pier 4 (the San Juan cruise terminal). Recurring contamination was found in a storm drain system, as well as in the harbor, and response crews used vacuum trucks and absorbent boom for three weeks to clean it up. The responders suspected that the source might be somewhere in a network of buried oil pipelines that dated back to the early 1900s.  

Manhole contaminated with heavy oil from the 2021 spill (USCG)

The response crews are now planning an underground survey to find and assess the condition of long-abandoned oil pipelines that were buried in the area in the early or mid-1900s. The lines are no longer in service, but they may well have some residual oil inside.

Samples of the 2021 and 2024 leaks have some similarities, according to the Coast Guard, and might come from one common source of petroleum leaking into the storm drain system. Like last time, the response team plans to do a subsurface site assessment to determine the extent of any soil contamination and determine the source of the spill.