Wal-Mart yesterday announced that it was the newest company to join the Coalition for Responsible Transportation (CRT), an innovative private-sector initiative aimed at addressing environmental issues caused by the shipping and trucking industries.

Wal-Mart's announcement means that it has committed to reviewing all of its logistics providers working in the ports to make sure that trucks being used to offload goods from the ships meet the emissions standards at the ports.

The Coalition is working to bring clean-truck technology to ports around the country. It launched in August 2007 with the Los Angeles and Long Beach ports in California, which enacted strict emissions guidelines and operating restrictions on ships in the port.

The rules stipulate that, beginning in Sept. 2008, the two ports will no longer allow trucks built before 1989 to enter the port facilities. That year was chosen as the date when pollution controls began coming pre-installed in most big rigs. The project's next phase, which will go into effect in 2012, moves that manufacture date up to bar any trucks made prior to 2007 from operating in the ports.

The CRT was created by the retailer Target Corp. and logistics companies NYK Line and TTSI Trucking, and has since been joined by companies including Nike, Home Depot, Lowe's and now Wal-Mart. Two other shipping companies have joined the group as well: Southern Counties Express and California Multimodal LLC.

Wal-Mart's move comes amidst a wave of news about the environmental impacts of the shipping industry. Last week, shipping company DHL said it had completed the first voyage of its Skysails technology, which uses wind power to help improve fuel economy and reduce pollution; a report also released last week found that ship-related emissions, at 3.5 percent of global carbon emissions, were grossly underestimated and nearly double than previous estimates of 1.4 percent.