Waste Management Inc. net earnings plummeted in the third quarter, hurt by lower commodity prices and charges from an organizational restructuring, a labor dispute and from investments.

The Houston-based Waste Management reported that net income for the period ended Sept. 30 dropped 21.3 percent to $214 million, or 46 cents per diluted share, compared with $272 million, or 58 cents per diluted share, for the year-ago quarter.

Revenue slipped 1.7 percent to $3.46 billion compared with $3.52 billion for the 2011 period, according to a news release.

A decline in commodity price declines in the company’s recycling and waste-to-energy prices resulted in a revenue decrease of $176 million and a 10-cent reduction for earnings per share in the quarter.

Waste Management said net income would have totaled $285 million, down $10 million from 2011, if not for charges of $32 million for the restructuring and union dispute, and $39 million from impairments of investments.

The company said it is lowering its earnings guidance for the year because it expects an additional 7-cent reduction per share in earnings from what was previously predicted because of lower commodity pricing. Waste Management now is setting its guidance range at $2.08 to $2.13 per diluted share for the year.