At blood banks in Orlando, Fla., lines stretched around the block as people waited, in some cases for hours, to donate blood in support of those wounded in a deadly attack at a local gay nightclub.

But, as some people noted with frustration and anger, FDA restrictions currently bar sexually active gay and bisexual men from donating blood, leaving many members of the LGBT community unable to contribute.

As Sunday evening approached, many of the city's blood banks reported that they were at capacity, thanks to the enormous outpouring of support — but called for donors to return on Monday and Tuesday, as the need would continue.

NPR's Hansi Lo Wang visited one of the city's blood banks on Sunday afternoon and reported that the bank had been forced to turn people away for hours because of the enormous response.

"Talking to some of the workers here at the blood bank, they said that they've never seen a response like this since, really, Sept. 11," he said on All Things Considered. "At one point, they estimated 600, 700 people were just at one of their blood banks here."

Hansi talked to one man — with much-needed O-negative blood — who waited in line for seven hours to donate.

"They also had a truck here serving shaved ice and free food," Hansi says. "These are all community groups and volunteers that just showed up on their own, called the blood bank and said, 'I think you probably need something to feed and cool down all the people waiting to give blood.' And they came and showed up and have been here for hours."

Meanwhile, there was fierce debate — and some confusion — over FDA rules restricting the ability of gay and bisexual men to donate blood.

For decades, the Food and Drug Administration has completely barred men who have had sex with men from donating to blood banks. The FDA said the ban was in place to avoid the spread of HIV.

Late last year, the FDA modified the rule; now, a man who has had sex with another man within the last year cannot donate blood. The change means there's no longer a lifetime ban on donating, but it still prohibits sexually active gay men from giving blood.

In the wake of the attack on the Pulse Orlando, a popular gay club, many on social media decried the rule:

Some called for straight allies to donate on behalf of gay and bisexual men who cannot.

A rumor also circulated that the restrictions on gay men donating blood had temporarily been lifted, given the dire need. Local blood banks quickly noted that the rumor was false, and that all FDA rules are still in effect.

In fact, Hansi reports, at least some Orlando blood banks are still operating under the former rules — not allowing men who have had sex with men, even if it was more than a year ago, to donate blood.

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