The American Red Cross warned Monday that its national blood supply has fallen to “critically low levels” and that donations are urgently needed for hospital patients.

The organization blamed “back-to-back months of worsening climate-driven disasters” and lower donor turnout due to Americans being busy with travel and back-to-school activities, leading to a shortfall of 30,000 donations in August alone.

Since early August, the Red Cross’ blood supply has plummeted by nearly 25%, potentially threatening the medical care of patients who need blood in emergencies as well as those living with critical conditions that require regular transfusions, including cancer and sickle cell disease. Blood distributions continue to outpace donations, the organization said.

The Red Cross said Hurricane Idalia last month caused more than 700 units of blood and platelets to go uncollected in the southeastern U.S.

The organization said it is closely monitoring Hurricane Lee and its potential impact on the Northeast, which could further limit its ability to collect blood. 

“For so many patients living with urgent medical care needs, crises don’t stop with natural disasters,” Dr. Pampee Young, chief medical officer for the American Red Cross, said in a statement. “In fact, in some instances the stress of a disaster can lead to a medical crisis for some individuals battling sickle cell disease.”

Young added that someone in the United States needs blood every two seconds, calling it “an often-invisible emergency that the rest of the world doesn’t see behind closed hospital doors.”

“Now, that urgency has only heightened,” he said.

The Red Cross supplies about 40% of the nation’s blood donations and is relied upon by 2,500 hospitals and transfusion centers. 

It said donors of all blood types are urgently needed and that there is an emergency need for platelets and type O blood. 

Anyone interested in donating can make an appointment using the Red Cross Blood mobile app, visiting RedCrossBlood.org or calling 1-800-RED-CROSS.