HOUSTON (AP) _ Stock of Waste Management Inc. plunged today after the nation's largest trash hauler disclosed it anticipates second quarter and annual earnings to be at least 10 percent lower than Wall Steet expects.

At noontime, Waste Management stock was off 36.6 percent from Tuesday's close, falling $19.62 1/2 to $33.93 3/4.

The company announced today it expects a $250 million shortfall in its solid waste operations projects and said that will produce second quarter earnings of between 67 cents and 70 cents per share, well shy of the 78 cents expected by analysts surveyed by First Call Corp..

For the year, Waste Management expects earnings to be in the $2.65 to $2.70 per share range, short of analysts' $3.02 expectation.

However, both totals will mark increases from last year, when Waste Management earned 41 cents for the second quarter and $1.82 for the fiscal year.

``Although we are disappointed with the revised projections, we remain proud of our accomplishments over the past 12 months,'' Waste Management chief executive Rodney Proto said in a prepared release. ``And the fact that the new full-year 1999 earnings expectation still represents a minimum of 46 percent improvement over comparable 1998 results.''

The company is investigating why business has slacked off and will provide more details when earnings are formally reported Aug. 3, Proto said. Revenues weakened toward the end of the quarter and the shortfall will ``similarly impact'' future quarters, he added.

Waste Management had $12.7 billion in revenues last year.

A year ago, Houston-based USA Waste Services and Oak Brook, Ill.-based Waste Management Inc. combined in a $13.5 billion merger, which created largest U.S. trash hauler. The new company is based in Houston.