A small army of blood technicians clad in red T-shirts, holding posters, banners and pennants raised their voices outside all four corners of the American Red Cross Building yesterday afternoon.

"Red Cross, double cross," employees chanted outside of the blood donation center along Spring Garden Street.

About 100 union members of Local 5103 of the Health Professionals and Allied Employees began striking yesterday morning as they fight for changes to their contract concerning safety, pay, scheduling and staffing.

Union members also struck at six other locations in Philadelphia, Willow Grove and New Jersey.

Discussions between HPAE and the Red Cross ended Monday night without an agreement, said Jeannemarie Otersen, HPAE's public policy director.

"We don't want to be out here," said union member and donor collection assistant Marisol Homs, 30, of Northeast Philadelphia. "We didn't ask for this, we just want a fair contract."

Though strikers said they fear for the safety of those they draw blood from, Red Cross spokesman Anthony Tornetta said blood donations are safe and he does not anticipate a blood shortage if the strike continues.

"If [the strike] does impact blood supply, we have the ability to go to one of our regional banks," Tornetta said, standing in a nearly empty blood donation center.

As Tornetta reassured the safety of the Red Cross's blood supply, the doors of the blood donation center were locked behind him. One employee was left behind, taking blood from a man who wished to donate platelets.

Tornetta said those wishing to donate blood should call 1-800-RED-CROSS before traveling to a facility.