The battle between carriers and shippers over costs has generated an unintended side effect that could have a sharp financial impact on both. It's a development carriers, shippers and the rest of the industry ignore at their peril.

As West Coast Editor Bill Mongelluzzo reports on the front page, anger at the lot of harbor truck drivers has moved beyond general complaining and focused on a tactic that could produce results. Teamsters union organizers demanded last week that a major steamship line's marine terminal in Seattle hire the drivers who serve it as direct employees instead of contracting the work out.Such move would clear the way for the drivers to become union members. It would change the face of terminal operations in the Pacific Northwest and far beyond. And it could significantly raise costs for carriers and shippers.

Harbor truck drivers are the collective low man on the intermodal-industry totem pole. Carriers and major shippers tend to be large organizations with economic clout. Longshore workers who man the terminal gates are organized into powerful unions that look out for their interests. Most harbor truck drivers, however, are independent contractors, owner-operators who work for local trucking companies. They have neither deep pockets nor union support; independent contractors aren't allowed to bargain collectively with employers.

Many drivers are paid by the trip, not the hour. They're at the very bottom when the complex system of moving containers through a port backs up, even briefly, and trouble rolls down the hill. A congested terminal or an unproductive gate operation can limit them to one trip per day, when they need two or three to cover their costs and show a slight profit.

(Nor is their lack of status limited to the marine terminal. In Elizabeth, N.J., earlier this month, the mayor and county manager were incensed by a high-handed move by the Port Authority of New York and New Jersey and Continental Airlines to keep a tract of land off their tax rolls. They struck back by stopping and inspecting trucks serving the busy port complex there. Some 600 tickets were handed out over three days to harbor truck drivers - who had nothing to do with the dispute - and traffic was seriously delayed, costing them even more money.)

Needless to say, the drivers have hardly been in an advantageous position to deal with the industry's crushing financial pressures. In an era when major retailers were able to dictate take-it-or-leave-it rates to shipping lines on the Pacific - as they did in the mid-1990s, when rates on imports from Asia dropped by 20 percent - the drivers didn't fare well.

Carriers, their revenues cut, reduced what they paid to harbor trucking companies. They in turn lowered their rates to drivers. Will the process work in the other direction, now that the market has changed and carriers have been able to raise rates in one direction on the Pacific? To judge from the vehemence of the drivers and their advocates, it hasn't yet.

Some critics add that the dearth of revenues also kept carriers from putting money into improving equipment and operations that would have raised productivity at their terminals, although blame for the operational problems can be spread widely.

Driver unrest turned into a three-week strike this summer at the Port of Vancouver. That was resolved, but anger and the threats spread south. Much of it was rhetoric broadly aimed at port officials and the port community in general. And, as has happened in other ports at other times, there were talks and efforts aimed at organizing the drivers.

Traditionally, however, organizing has been difficult because the drivers, often recent immigrants, have been less than enthusiastic about joining a union. And, of course, the drivers' status as independent contractors has been both a legal and an organizational barrier.

But the Teamsters demand that the APL Ltd. terminal at Seattle hire harbor drivers (and recognize the union) represents a new and more focused approach - and a far more serious one. While it doesn't deal with drivers' attitudes toward unions, it does address the independent-contractor issue.

Clearing that barrier would open the way for a full-fledged organizing campaign by the union. Key selling points would certainly be the union's desire, ability and strength to improve the lives and bargaining position of the drivers.

And a successful organizing drive would not stop in Seattle. It would encourage the Teamsters, other unions and drivers in ports around the country. It's unlikely, given the differences between ports, that a monolithic drivers' union would emerge. But one way or another, there could be a lot of battles over unionizing harbor truck drivers, and a lot of added costs for carriers and shippers.

The Teamsters challenge is likely to jolt shipping companies and big shippers industrywide. It should. Their single-minded focus on their duels over rates helped bring it about. That's not to say either side can afford to be casual about rates. But neither can they continue to act as if they exist in a vacuum. The driver situation in Seattle - and its potential to spread - shows they don't.