Just days before a key vote on a controversial Southern California drayage overhaul plan, Los Angeles port officials quietly changed key details of their version of the plan, threatening to derail the two ports' plan to cut diesel emissions in the nation's busiest container port complex.

The change, done with no public announcement, effectively creates two distinct multiyear truck plans for the San Pedro Bay port complex. It also sets the erstwhile and neighboring port competitors of Long Beach and Los Angeles on a path that will see the former adopting a longer-term more aggressive emission reduction plan, and the latter set to vote on a quicker-to-market, but less aggressive and ultimately more polluting version.

The issue began last Thursday, when in a coordinated effort the ports of Long Beach and Los Angeles announced that they would vote this week -- Long Beach today, Los Angeles on Thursday -- on a stripped-down version of their jointly developed $1.8 billion truck plan.

The overall plan, which began life several years ago as a simple funding concept to cut diesel emissions by replacing older trucks in the port drayage fleet, morphed earlier this year into a truck re-regulation plan that also included labor and wage regulations that would force drivers to give up their independent driver status. Analysis of the plan, as introduced by the ports in March, estimated that more than 6,000 trucking industry workers were at risk of being forced out of the industry on the then-proposed implementation date of Jan. 1.

The retail, shipping and trucking industries have unanimously agreed with the clean air goals of the ports' plan, while vehemently opposing the labor and funding components, calling the total plan unworkable.

Environmental groups, though still committed to the plan's original format, have grown weary of the ports' delays in implementing the plan and critical of the ports' apparent backsliding on the labor components.

Labor groups such as the International Brotherhood of Teamsters union, which originally pitched the labor component to Los Angeles Mayor Antonio Villaraigosa last summer, have remained vocally supportive of the ports' plan and spent hundreds of thousands of dollars through front groups to lobby support for the truck plan among the local communities.

On Thursday, the ports' announced that their governing boards would each vote to change their respective tariffs -- the operating bylaws of each port -- to force terminal operators to progressively ban certain model years of trucks.

Under the tariff proposals released Thursday by the ports, terminals would have to bar entry to all pre-1989 model year trucks beginning Oct. 1, 2008. On Jan. 1, 2010, terminals would have to block all 1989 to 1993 model year trucks as well as 1994 to 2003 model year trucks without retrofitted emission control devices. Both tariff changes also called for a third round of bans, with Jan. 1, 2014 set as the date all pre-2007 trucks would be barred from entering port facilities.

Because the two adjacent ports are considered one port complex by most of the goods movement industry -- in fact many individual trucks service facilities at both ports daily -- both ports released identical tariff change proposals. The ports understood from the beginning of their joint environmental efforts last year that the success of any plan depended on both organizations developing identical and non-conflicting language. So much so, that last August the ports petitioned the Federal Maritime Commission to allow officials from Long Beach and Los Angeles to meet and jointly develop environmental programs. Normally this is prevented by antitrust regulations, but the FMC agreed to the ports' collusion on certain projects. The two ports' governing boards would still have to approve any jointly developed project, but since the plans were being developed jointly by both ports' staffs, until now both harbor commissions have voted on the same material.

Sometime after Thursday's releases by the two ports, and with only minimal notification to Long Beach officials, the Port of Los Angeles quietly changed a key detail of their version. The modified Los Angeles tariff proposal now calls for an entirely different implementation timeframe. While the first ban -- pre-1989 trucks on Oct. 1, 2008. -- remains the same, Los Angeles port officials changed the second and third ban dates and what they cover.

The second ban date of Jan. 1, 2010 now calls for all pre-2004 trucks to be banned outright, unless they are a model year 1993 to 2003 truck equipped with a retrofit device. This seemingly minor change adds 10 years worth of truck models to the total that will be banned on Jan. 1, 2010 compared to the tariff proposal released Thursday by Los Angeles.

The Los Angeles changes also accelerate the third and final ban implementation date by two years from Jan. 1, 2014 to Jan. 1, 2012. In addition, the first Los Angeles proposed tariff called for the third ban to block all trucks that do not meet 2007 state and federal emission standards by the start of 2014. The updated changes now specifically make an exemption from the third ban for 1994 to 2006 trucks that have been retrofitted. Studies show that 2006 model year trucks are drastically more polluting than 2007 model year trucks. This means that though Los Angeles' new timeframe would have two years with tighter emission standards than Long Beach, after 2014 Long Beach's proposed standards would be more stringent from then on. The 12 years of retrofitted trucks -- 1994 model years to 2006 model years -- would still be able to operate at Los Angeles facilities for the life of the vehicles.

It should be noted also that there are no known retrofit devices available for 2004 to 2006 trucks, due to technology incorporated into the engines during those years.

Insiders close to the truck program at the port of Long Beach, who asked that they not be identified, said notification from Los Angeles about the changes came suddenly and as a surprise to Long Beach staff. They conjectured that by changing to an accelerated timeframe so close to the vote dates, Los Angeles was attempting to force Long Beach officials to go along with the more accelerated 2012 date.

The new changes were posted to the Port of Los Angeles Web site after the close of business hours on Friday and without a notification being sent to members of the press that were notified of the original tariff rule proposal on Thursday.

Moreover, the changes were not noted on the Los Angeles port's Web site and the proposed tariff update was uploaded over the original file dated Thursday, giving it the same name and thus the appearance of being the same file that was uploaded on Thursday. The press release that was issued on Thursday by Los Angeles port officials was also modified with the new ban timeframes, but the issue date of the release still indicates that it was released Thursday.

The move highlights a growing rift between the two ports over what the focus of the truck plan should be.

During a public meeting Oct. 12, commissioners from the Port of Long Beach made it clear that they wanted to move forward with the clean air portions of the original plan, even at the expense of dropping the two ports' previously stated goal to make all truck drivers employees of a handful of large trucking firms.

Long Beach commissioner Mike Walter suggested the two ports need to keep their focus simple regarding the truck plan. "I want to address, first and foremost, those items that directly affect pollution. And the base case I want has nothing to do with the issues that are not related directly to pollution."

In response, Los Angeles commissioners reaffirmed his board's commitment to the labor portion of the plan.

"The idea that we can not deal with a program that deals with all three of these issues [pollution, security, and labor] is completely unacceptable," said S. David Freeman, president of the Los Angeles harbor commission.