Refineries not running at full tilt

WASHINGTON

U.S. refineries churned out 87.6% of the gasoline that they were capable of producing last week, down from 89.2% the week before and 5.7 percentage points below a year ago, the government said Wednesday.

The drop came at a time when gasoline production is usually rising to meet summer demand. But aging refineries, continued maintenance following hurricanes in 2005 and greater complexity in refining is forcing refineries to shut down lines.