The rigorous inspections were unusual. Inspectors are often so overwhelmed they may have time for only a cursory look inside containers, relying on instinct and experience to determine which cargo might pose the most risk to Hawai'i's environment.

"It's usually one person doing everything," said Sakaino, an inspector from Waipahu. "You just do what you've got to do. I'm sure that some things get through that shouldn't be going through."

For the past few months, the Department of Agriculture has been conducting evening sweeps of cargo at the airport, gathering data that may help inspectors identify patterns of risk. The department wants to know which Mainland flights, which types of produce or plant or animal shipments, are the most likely to bring invasive species to the Islands.

The sweeps, modeled after a similar effort at Kahului Airport on Maui a few years ago, involve intense searches of select cargo containers. Eventually, the department wants to extend the sweeps to mail and shipping containers so it can collect more information and more efficiently direct its inspectors in the future.

Carol Okada, plant quarantine inspector, watches for bugs falling onto a white sheet of paper while one of her co-workers shakes the fresh lettuce. Okada uses a small paint brush to pick up the bugs. Eugene Tanner • The Honolulu Advertiser

The odds are not in the inspectors' favor. During the day, about seven state inspectors watch over about 18 domestic flights, with two inspectors assigned to the cargo. At night, four inspectors look over about a dozen flights, with only one inspector in charge of cargo.

Inspectors keep a critical watch on cut flowers, plants and organic produce. They also check for contraband fish and other animals. The mission is to intercept alien plants, animals or diseases before they can take hold.

"It may not look like much. It may be only a few spots on a plant that may just seem very insignificant. But that whole shipment may be covered," said Neil Reimer, chief of the Agriculture Department's plant quarantine branch. "These guys are all dedicated to keeping that stuff out."

Inspector Carol Okada uses a magnifying glass to show the bugs found on some lettuce. The whole shipping crate was quarantined. Eugene Tanner • The Honolulu Advertiser

Lawmakers approved $300,000 this year to combat the coqui frog — one of the state's most persistent pests. Potentially devastating pests like the brown tree snake and the red imported fire ant have been kept out of the Islands, but inspectors say it is a daily test with limited manpower.

The sweeps, while instructive, have shown how easily things can be missed. A crew searching the cargo of a Hawaiian Airlines flight from Los Angeles set up folding tables and bright lights and went through much of the produce by hand. They put aside nine boxes of lettuce and marked about two dozen boxes of cilantro that contained suspicious insects. A box of green onions was held because of fungus. An entomologist would look at the produce overnight before inspectors make a decision.

"It's an impossible task," Reimer said, looking at the rows of cargo containers. "You just do the best you can."