American Red Cross Blood Drive in Glasgow Tuesday and Wednesday

Montanans are being encouraged to roll up their sleeves and donate blood as the nation continues to face a serious blood shortage.

The American Red Cross declared only the second national blood supply crisis in its history this summer after blood donations dropped to a four-year summer low.

The Red Cross says the shortage became so serious that it had less than a one-day supply of some types of blood, including O-positive—the most commonly transfused blood type. The organization has been forced to limit some distributions of Type O blood to hospitals.

All blood types are needed, but officials say Type O-positive and O-negative donors are especially important because those blood types are frequently used in emergencies and trauma situations.

The need is particularly important in Montana, where blood donations help supply hospitals and medical facilities across the state.

The American Red Cross of Montana collected more than 51,000 units of blood during the past year through more than 2,100 blood drives statewide. The Red Cross provides blood products to more than 30 hospitals and medical centers in Montana.