Traders fear oil shortage

Oil prices advanced to their highest level in a month Monday, surpassing $46 a barrel, as supply constraints in the United States and Russia piqued the nerves of a market already edgy about the world’s limited production capabilities and rising demand.

Cash-strapped Russian oil giant Yukos said it would halt some oil exports to China, while U.S. petroleum inventories are expected to decline again this week due to production, refining and shipping delays caused by Hurricane Ivan.

Neither factor is itself a punishing blow to the global supply chain, analysts said, though each is enough to test the nerves of traders already worried that there might not be enough excess output capacity to handle a more serious, prolonged disruption.

Aviation

Delta wins concession

Delta Air Lines’ pilots union agreed Monday to allow the struggling carrier to bring pilots out of retirement on a limited basis to deal with staff shortages that threatened to ground flights.

The tentative agreement must be ratified by the 7,500 active Delta pilots. The nation’s third-largest airline has warned that it would have to file for bankruptcy if it did not stem a wave of early pilot retirements by the end of September.

The agreement still does not resolve Delta’s larger problem: getting the pilots to agree to $1 billion in concessions.

Technology

AOL offers more security

Passwords alone won’t be enough to get onto America Online under a new, optional log-on service that makes AOL the first major U.S. online business to offer customers a second layer of security.

The so-called two-factor authentication scheme, being unveiled today, will cost $1.95 a month in addition to a one-time $9.95 fee. It is initially targeted at small businesses, victims of identity theft and individuals who conduct financial transactions through their AOL accounts.

Subscribers get a matchbook-size device, pictured above, from RSA Security Inc. displaying a six-digit code that changes every minute. The code is necessary to log on, so a scammer who steals a password cannot access the account without the device.