Invasive species found aboard military vehicles arriving at the Port of Guam have captured the attention of officials. The discovery of pests—some potentially harmful to the environment—has raised concerns over biosecurity measures for military cargo.

It was a routine unloading of military vehicles at the port, until workers discovered more than they bargained for: yellow crazy ants, spiders, and snails hitching a ride on Department of Defense humvees shipped from Tinian. The pests likely slipped through multiple inspections before arriving on Guam, according to state entomologist Christopher Rosario with the Guam Department of Agriculture's Biosecurity Division. 

"About two days ago, the cargo was released," he confirmed. "But prior to that, Matson had coordinated   with a local pest agency to perform a methyl bromide fumigation using– basically covering the whole cargo flat racks that it was on."

The yellow crazy ants are already a problem locally, but the spiders and snails pose a bigger mystery. "I could only identify the ant species. Because this ant species is distributed throughout Micronesia, the yellow crazy ants. The spider was identified down to the genus name which is a neoscona spider," he added.

There were three snail species on the cargo. So far, two of them have been identified down to the family name– amber snail and subulinid snail.  But it’s not about whether the pests are invasive or already established on Guam. With Guam being a major hub for Micronesia, they could hitch a ride to other islands. 

"My biggest worry," noted Rosario, "though with these layers of inspections being passed and that this was infested, this is cargo that had multiple organisms – invasives or natives, the Port Authority or any port of entry needs to stay sterile."

Rosario adds the Guam biosecurity officials and Customs immediately took action, fumigating the vehicles. But the discovery has raised new questions about how effectively military cargo is being inspected before arriving at Guam.

Typically, shipment of vehicles require a washdown before export. One video shows dirt still apparent on the humvee’s wheels. 

CNMI Customs and Biosecurity director Jose Mafnas told KUAM News they’re not in charge of inspections for military cargo shipments– it’s the DoD's jurisdiction, who has a contract the center for environmental management of military lands. 

"The sterility of the port yard is vitally important because if these invasives had perhaps sat for several days at the port, then it could potentially move to other cargo easily, whether it’s through wind or rain or simply just falling off of these cargo and hitchhiking onto other cargo," he said.

In the meantime, Guam Customs and Quarantine Agency public information officer Alana Afaisan Chargaulaf assures the community that officers assigned to board and conduct clearance procedures on this particular vessel did so in accordance with established protocols. 

STATEMENT FROM GUAM CUSTOMES AND QUARANTNE

First and foremost, we want to assure the community that the Guam Customs Inspection and Control (ICD) officers assigned to board and conduct clearance procedures on this particular vessel, at or around 8:55 a.m. on Sept. 29, 2025, did so in accordance with our established protocols, as expected.

Secondly, the military vehicles of concern, though offloaded from the vessel, have not left the sterile area at the Jose D. Leon Guerrero commercial port as of this point in time and, therefore, have not left our customs inspection jurisdiction. This same sterile area is where our Biosecurity Task Force (BSTF) officers, a special enforcement team separate from our ICD boarding officers, attended to the incident and carried out their respective established protocols. This was immediately upon receiving an alert at or about 8:18 p.m. via port personnel about the pest findings that same day.

To answer any questions of how our ICD boarding officers neither witnessed these pests for themselves, nor any buildup of dirt on the vehicles to prompt investigation: Conditions aboard the vessel were not conducive to safely maneuver around and assess the vehicles from the required vantage points. To note, vehicles were stacked and surrounded by obstacles and tripping hazards. Overall conditions at the time suggested that port personnel may proceed with the cargo offloading activities that were to follow, after customs officers conducted what extent of inspection was deemed safe and practical. We would also like to note the boarding officers observed water streaks on the vehicles while onboard the vessel, indicative that action was likely taken in accordance with required wash-down protocols for such exports.

We have made contact with Commonwealth of the Northern Mariana Islands Customs and Biosecurity to bring awareness to this situation and encourage collaborative mitigation efforts moving forward. We respectfully defer all inquiries concerning their operations to them to ensure you receive the most accurate and updated information.