Firefighter Jay Shaffer, 47, died Saturday afternoon of an apparent heart attack while testing for his Wildfire red-card in Larkspur, Colorado.

Shaffer was completing his 3-mile pack test to become certified to fight wildfires in 2001.

Survived by a step-daughter, Shaffer was a nine and a half year veteran of the Larkspur Fire Department, said Chief Keith Mathena. In addition to volunteering for the department, his interests included computers.

The Larkspur Fire Protection District serves 5500 people in a primarily rural area of 120 square miles. The combination department has about 12 paid members and 27 volunteers.