Shares of Waste Management Inc. plunged again, losing 17% as it said its second-quarter earnings will fall short of already lowered estimates, and its chief financial officer resigned. Waste Management said it expects to report profit of 58 cents to 60 cents a share next week. The announcement, coming just weeks after another profit warning, is another sign of the disarray at Houston-based Waste Management, the nation's largest trash hauler. In November, its chief executive had brain cancer surgery and hasn't been able to work full time since, and earlier this month investors filed lawsuits alleging executives engaged in insider trading. Now Waste Management has said it overestimated its trash revenue and incorrectly accounted for landfill closing costs and maintenance and repairs. Chief Financial Officer Earl DeFrates resigned for undisclosed reasons, the company said. General Counsel Gregory Sangalis also quit, saying that he could no longer represent the company because he and other executives are being investigated on insider-trading allegations. Waste Management shares fell $5.50 to close at $25.94 on the New York Stock Exchange.