Add ambulance operators to the growing list of companies having trouble finding workers. The Massachusetts Ambulance Association estimates the number of staffed vehicles has declined by more than a third since 2015, with the decline accelerating during the pandemic. Most other states are facing a similar decline. The “nation’s EMS system is facing a crippling workforce shortage,” the American Ambulance Association told Congress in October. The shortage is affecting patients across the country. Some remain in the hospital for an extra day waiting for a ride to a rehab facility. Nursing home residents are missing cancer treatment and MRI appointments. And patients who need specialized care are sometimes stuck waiting for a lift in community hospitals.