The American Red Cross has announced a critical shortage of blood donations, particularly for universal donor Type O, leading to an urgent call for donors across the nation. Donations have fallen to a four-year summer low, creating a situation where the organization at one point had less than a one-day national supply of Type O positive blood in late July.

"When blood donations decline, patients facing emergencies, cancer treatments and other serious medical conditions can feel the impact almost immediately," said Jacquelyn Clites, regional chief executive officer for the American Red Cross Los Angeles Region.

To address the crisis, the Red Cross is partnering with the International WeLoveU Foundation for several large-scale blood drives. One such drive is scheduled for Sunday at the Pasadena Convention Center, aiming for at least 300 appointments. Hundreds have already scheduled donations for the event, which will run from 9 a.m. to 3 p.m. at 300 E. Green St. Walk-ins will also be accepted.

Similar drives are planned for Sunday in Portland, Oregon, and Philadelphia.

Factors contributing to the low donor turnout this summer include extreme heat, poor air quality, and widespread foodborne illnesses, according to the Red Cross. The period between Memorial Day and Labor Day is often referred to as the "100 deadliest days" due to an increase in severe injuries from car and recreational accidents. A depleted blood supply can significantly worsen survival rates for those requiring transfusions.

"Every time a volunteer rolls up their sleeve, they’re making a decision that could save a stranger’s life within hours," said Jessica Amaya, a program manager with the WeLoveU Foundation. The Red Cross stated that a single car wreck victim could potentially require up to 100 units of blood.

Another blood drive is scheduled for Friday at Los Angeles County Fire Department Station 89, located at 29575 Canwood St. in Agoura Hills.