If workers are exposed to 92 dBA for 2 hours, 90 dBA for 2 hours, and 85 dBA for 4 hours in the workplace, what percent of their daily noise dose would they receive using the hearing conservation limits? Briefly discuss the Occupational Safety and Health Administration (OSHA) requirements for evaluating this exposure related to a hearing conservation program, and explain the requirements for engineering controls and the use of hearing protection.