The 2002 NASCAR rulebook now requires that all crew who go over the wall must wear helmets. All crew members in the pit must wear fire-resistant suits. Fuelers are required to wear full-race helmets and flame resistant balaclava (head sock). In the past, NASCAR has strongly recommended wearing safety gear in the pits.
NASCAR recommended helmets for the over-the-wall crew members for the final two races of the 2001 season due to the injuries to Ricky Rudd's crew members at Homestead-Miami Speedway.
The helmets are to protect against possible head injuries while the fire-suits will increase protection in case of a pit fire. The new ruling includes all team members who go over the wall. It also includes crew members who transport fuel in the garage area.
Crew members are not the only team members who have new safety rules. Winston Cup drivers will wear fire suits and helmets during all official track sessions (practice, qualifying, race). In the past, it has only been a recommendation.
NASCAR will also require that all "over the wall" officials wear helmets.
Also fire extinguishing equipment must be located inside the race car within the driver's reach and must have a visible, operative pressure gauge. And the "black box" data recorders will be required in all race vehicles.
The 2002 rulebook covers all safety equipment with statements that they must be worn in compliance with the manufacturer recommendations at all times. An example of this type of statement was covered previously by NASCAR in regard to seat belts.
These now mandated, not just recommended, safety changes are to ensure a safer environment in racing. Unfortunately, as in all motor sports, accidents will happen and the outcome of said accident can not be predicted by any sanctioning body.
Official NASCAR release.