West Texas Intermediate oil declined for the first time in a six-day period on Monday amid speculation that inventories in the U.S. might increase after Exxon Mobile Corporation closed the Pegasus pipeline. May WTI futures decreased by 77 cents, or 0.8%, to $96.46 a barrel on the NYMEX after the contract rose to its highest since February 14 at $97.23 on March 28.