Oil prices hit four-year lows Friday as employers cut the highest number of jobs in 34 years. The continuing decline in prices is so dramatic and so sudden that it is raising the prospect that gas prices could soon reach $1 a gallon.

Crude prices plunged immediately, at one point reaching $40.81, after the Labor Department reported a half million people had lost their jobs in November.

Demand for fuel has withered amid an economic tailspin, as companies cut back production and slash jobs.

Light, sweet crude for January delivery fell to $2.47 $41.20 a barrel on the New York Mercantile Exchange by early afternoon.

The Labor Department reported that employers slashed a far worse-than-expected 533,000 jobs and the unemployment rate jumped to a 15-year high of 6.7 percent. Analysts were looking for job losses of 320,000.

It was the sixth straight day of declines for crude prices, with each release of new economic data outlining a stunning deterioration for the U.S. economy. Earlier this week, the National Bureau of Economic Research determined that the U.S. has been in a recession for a year.

Since the start of the recession, the economy has lost 1.9 million jobs, the number of unemployed people increased by 2.7 million and the jobless rate rose by 1.7 percentage points.

Crude prices have fallen 72 percent from record July highs.

“At this point, it’s just keeps going, going and going,” Peter Beutel of Cameron Hanover.

Crude could soon reach levels last seen in July 2004 when prices were last below $40 a barrel.