The New York Blood Center has declared a blood emergency heading into the Fourth of July holiday weekend.

Officials say supplies have dropped below required minimums, even for the seasonally low summer months.

"People are away or, you know, they are otherwise occupied during the holiday," says Mike Suehle, of Brooklyn Blood Center. "It's just even more important for people to come out and to donate blood platelets, red cells, whole blood, anything they can."

Donating is simple and easy, taking under an hour from start to finish. Donors say it feels good to make a difference.

"That I have the impact or that I have the ability to save somebody's life is really meaningful," says Emily Chin, who donates blood three times a year.

Type O-negative donors, like Elizabeth Pongo, are considered universal because their blood type is in particularly short supply and can be used by anyone in need.

"I think it's really important to donate blood because it’s something that every citizen can do to help out people on a global level," Pongo says.

Donating just 1 pint of blood can save up to three lives.