The pressure to upgrade security is high at Caribbean ports because if they fail to meet new standards by July 1, they could lose one key advantage they have over export giants like China: proximity to the United States.

"That would be disastrous," said Arsenio Borges, director of ports in the Dominican Republic.

Santo Domingo's largest port, Haina, and others are spending millions of dollars hiring guards, putting up chain-link fences and installing computer programs, X-ray machines for screening containers and surveillance equipment to meet the new global security rules.

While bigger Caribbean countries such as the Dominican Republic and Jamaica are on track to meet the requirements, port experts worry smaller cash-strapped nations may not make the grade.

And if the United States turns away or performs lengthy inspections on ships from noncompliant ports, that could deliver a blow to the estimated $20 billion per year in U.S.-Caribbean trade.

Even if ships from the Caribbean are delayed a few days, that could be enough to make importers consider getting products from elsewhere, said Anthony Bryan, director of Caribbean studies at the University of Miami who is overseeing a port study. He said China's ports would be the winners.

The United States is the largest trading partner of many Caribbean countries, including the Dominican Republic, whose textiles, sugar and other goods already struggle to compete internationally.

The new rules established by the International Maritime Organization also could affect the cruise line industry -- a lifeline for Caribbean economies heavily dependent on tourism.

Any ship docking in the United States will have to produce documents showing the last 10 ports visited comply with the rules. Because cruise ships run a tight schedule, ports that cause delays might be skipped.

"We have a lot of concern that a number of the smaller ports won't make the schedule," said Ted Thompson, vice president of the Arlington, Va.-based International Council of Cruise Lines. He said the group estimates tourists docking in Caribbean ports spend $2.5 billion a year.

The United States is offering technical assistance on meeting the new rules, but what small nations need most is money, said Lt. Cmdr. Leighton Bennett of Jamaica's coast guard. Bennett heads the Caribbean Memorandum of Understanding on Port State Control, an agency overseeing regulations in 12 countries. He said half of those countries may not be able to afford upgrades.

Jamaica has spent more than $50 million to boost security and still has more to do, Bennett said. The Dominican government won't disclose what it has spent, but port officials say it's in the tens of millions.

In January, Trinidad and Tobago's government spent $3.3 million for consultants to come up with a security plan.

The U.S. Coast Guard will inspect a handful of overseas ports each year to determine whether they are complying, said Capt. Kevin Dale, the Coast Guard's chief of port security. Other ports will simply turn in documents describing their security programs.

Ships that pass through noncompliant ports will likely face delays when they arrive at U.S. ports, Dale said. And for those ports, he said, "the ultimate sanction would be that companies use other ports."

An employee scans an ID card at the entrance to Santo Domingo's Haina port in Costa Rica. The port is spending millions on security measures. Containers await inspection at the Haina port. Caribbean nations are working to meet security standards prompted by the Sept. 11, 2001, attacks.