The U.S. Consumer Product Safety Commission said switches may activate the mower "when the operator vacates the seat," which raises the risk of an injury from the mower blades.
The mowers involved in the recall are large commercial duty ZRT mowers -- ZRT standing for zero radius turn. They were sold with 52-inch and 72-inch cutting decks.
The recall involves mowers with model numbers 74264, 74265, 74266, 74267, 74274, 74253 and 74254.
Various serial numbers also define which mowers are involved in the recall.
The mowers were sold from September 2005 through January 2011 for between $13,000 and $17,000 each. An additional 109 mowers were sold in Canada.
Machines, which have a light gray optional deluxe seat with an adjustable knob on the front, are involved in the recall. Consumers with these mowers were advised to contact a Toro dealer for instructions on how to modify the seat or to have a repair scheduled.
Consumers can call 866-946-3109 for information.