EUGENE, Ore. -- The family of 4-year-old Isabelle Norton seeks more than $8.5 million from the company that manufactured the riding mower that backed over her leg, causing it to be amputated.

Norton's father, Kirk, was mowing the lawn at the family's Springfield home when the accident happened in May 2006.

The lawsuit alleges that Deere & Company was negligent in designing the mower with a switch that allows the driver to keep the blades spinning while driving in reverse. The lawsuit also names the seller, Ramsey-Waite Co. of Eugene, alleging the company did not adequately instruct Kirk Norton in the safe operation of the mower.

Frank Bonser, the Ramsey-Waite general manager, said the company did not have enough information about the lawsuit to comment Tuesday.

John Deere Co. spokesman Ken Golden said the mower Norton was driving disables the cutting blades when driven in reverse, unless the driver overrides the safety mechanism by flipping a switch.

"John Deere prides itself in safety," Golden said. "We have a long record of safety mechanisms that are built into our products."

Eugene lawyer Don Corson, who filed the suit, said other manufacturers have made safer designs, and the suit aims to persuade Deere & Company to do the same.

Norton's left leg was amputated at the hip. The lawsuit seeks $5.25 million for the girl's pain, suffering and loss of physical ability, and $2.6 million for medical treatment, therapy and loss of earning capacity.

No trial date has been set.

About three months after Norton was injured, a 2-year-old boy was struck and killed by a lawn mower at a home south of Veneta.