Checking the background of U.S. port workers, as the Bush administration announced last week it would begin doing five years after promising such reviews, is a positive, if belated, step. Such reviews will be more useful if they are coupled with legislation sponsored by Sen. Susan Collins that requires tracking and inspection of cargo entering the country, not just the people handling it.

Ensuring the 400,000 people who work at U.S. ports are not on terrorist watch lists and providing tamper-resistant identification cards to the 750,000 workers – including truck drivers – who have easy access to shipping containers will diminish the risk of an attack on American ports. A larger problem, however, is that the large majority of goods consumed in the United States come through its ports, though only about 6 percent of it is screened.

Shipping containers have been used to illegally transport weapons, drugs and people – a bomb could be next. Working to ensure cargo containers headed to the United State don’t contain bombs or their components is just as important as ensuring longshoremen don’t have ties to terrorist groups.

Improved cargo screening is a cornerstone of Sen. Collins’ legislation. The bill, co-sponsored by Sen. Patty Murray of Washington, has five parts: standards for cargo security; higher standards that give shippers preferred treatment under a voluntary program called GreenLane, which tracks their cargo from factory until it reaches the United States; protocols for restarting port operations after an attack; $400 million for security grants for ports; and deadlines and accountability for the Department of Homeland Security to ensure port security occurs.

The deadlines are important because the department continues to make excuses for not inspecting more cargo. There are models for the United States to follow. Every container leaving Hong Kong’s terminal is scanned and passed through a radiation detection device. Sen. Collins’ bill would encourage other terminals to take similar steps, by expediting trade with countries that participate in a global cargo container inspection system.

Until the Dubai ports debacle, port security got little attention in Washington. Maybe there’s reason for that since U.S. ports have been vulnerable for decades but have not been attacked. However, if the goal is to get bombs or other weapons into this country, seaports would be a likely target.

Port security improvements, however, must be well thought out and not simply quick fixes such as belated background checks. The Collins-Murray legislation is a methodical approach to improving port safety. Together with the new identity checks, it will improve security at American ports.