An 18-inch wastewater sewer pipe broke on Joint Base Pearl Harbor-Hickam today spilling 14,000 gallons of sewage — with the Navy saying the increased activity on base may be to blame.

Rim of the Pacific, the world’s largest international maritime exercise, has started with 26 nations, 45 ships, five submarines, more than 200 aircraft and 25,000 personnel operating mostly in and around the Hawaiian Islands, but also in Southern California.

Navy personnel responded to a call at 8 a.m. after sewage spilled onto Porter Avenue between Wilson and Owen Streets on the Hickam side of the base, Naval Facilities Engineering Command Hawaii said in a release.

Crews were dispatched and completed the installation of a bypass line, stopping the spill at 10 a.m.

“Specific cause for the break is unknown at this time; however, due to increased activity at the base” the wastewater system is handling a larger volume of sewage flow, the Navy said. “Assessment of the break and future repairs or replacement of pipeline are currently underway.”

Approximately 14,000 gallons spilled from the broken line, with 5,000 gallons contained on land and recovered by vacuum truck, and the remaining 9,000 gallons entering a nearby storm drain, the Navy said. The storm drain leads to a canal and discharges at a location east of Hickam Beach.

“The Navy has made all necessary notifications to the state Department of Health as required by the wastewater treatment system’s operating permit,” the Navy engineering command said. “Navy environmental personnel have inspected the affected areas. At DOH direction, and as a measure of precaution, warning signs are being posted near and around the exit of the storm drain canal and at Hickam Beach.”

The Navy said it will also conduct water monitoring to determine near shore water quality impacts.