OKLAHOMA CITY - The main source for blood for almost every Oklahoma hospital is facing a critical shortage. 

Officials with the Oklahoma Blood Institute said they are in desperate need of Type O-negative donors.

“Right now, we're at less than a one-day supply for O-negs, so we are not comfortable at all,” OBI Executive Director of Community Relations Tara Scott said.

Type O-Negative can be universally donated in case of an emergency.

Scott said the OBI contributes 90% of the state’s blood supply.

“With less than a one-day supply, the o neg inventory is actually critical,” Scott said.

Fortunately for the OBI, current donors speak highly of the process.

Justin Vanbrunt said he’s donated blood or platelets to the OBI more than 90 times.

“It's very important. O-negative is pretty rare so if you've got it you should definitely try to help out,” Vanbrut said of the process.

Blood must be given by volunteers days ahead of transfusion, as donations take a while to process.

“When a disaster strikes, the people who give blood regularly and make sure we are at that two to three=day supply for the community, those are your true heroes,” Scott said.

Anyone interested in donating blood in Oklahoma can visit the OBI’s website or just drop into a location during open hours.