An increase in recent trauma cases in the Central Valley, paired with centers facing a decrease of donors, has resulted in less than one day supply of type O blood.
Unable to keep up with collections, organizers say hospitals run the risk of not treating patients properly.
The Central California Blood Center provides blood and services to patients who receive care at 30 hospitals across the region.
Officials say they need 5,000 to 6,000 pints of blood collected per month.
For more information on how to donate, visit the Central California Blood Center's website.