HARRISBURG – The American Red Cross says blood donations have fallen to a four-year summer low, worsening the emergency shortage, and threatening patient care. Despite thousands of people answering the call to give, blood donations are not keeping pace with hospital demand, which is up during the summer trauma season. Extreme heat, poor air quality, and widespread food borne illnesses are contributing to lower donor turnout this summer, further straining the nation’s blood supply. As the nation’s largest single provider of blood products, the Red Cross now has less than a one-day national supply of type O positive blood – the most commonly transfused blood type. To help ensure blood is available for patients facing the most critical, life-threatening emergencies across the country, the Red Cross has begun limiting distributions of type O blood to individual hospitals. Persons can make an appointment to give blood now by visiting RedCrossBlood.org or calling 1-800-733-2767.