The California Environmental Protection Agency's Air Resources Board has delayed two compliance deadlines for diesel transport refrigeration systems to meet standards set by the board's Airborne Toxic Control Measure.

The board extended registration for transport refrigeration units and operator report requirements to July 31, That deadline previously was extended from Jan. 31, 2009 to March 16. Enforcement of the new measure begins in August.

The board also moved the deadline for meeting low-emissions in-use performance standards for refrigeration units with 2001 and older engines to Dec. 31. That was originally set for Dec. 31, 2008, but delayed to mid-July. Enforcement of these standards begins in January, for all model year 2002 and older engines, according to the board's Web site.

According to that site, the delays are necessary because several thousand of the transportation refrigeration units were not in position to comply by mid July. The reasons included lack of timely action by owners, higher costs than anticipated, some retrofit systems not becoming available until May, tightening of credit, and longer lead times for delivery of systems.