People are lining up to give blood, but officials say if you really want to help, wait a few weeks and then come in to donate.

There can be too much of a good thing.

Even when it comes to donating blood.

People have been lining up to donate the precious liquid after the mass shooting in Las Vegas and the hurricanes that hit Houston, Florida, and Puerto Rico.

And that’s a problem.

Blood bank officials explain that blood can only be stored for about six weeks. So if everybody gives now, a lot of that blood may need to be thrown away.

If you want to help, the officials say, wait a few weeks or even a month and then donate.

Better yet, become a regular donor.

“Volunteer blood donors are needed each and every day to help save lives,” the American Red Cross said in a statement.

Blood banks had enough supplies on hand when nearly 60 people were killed and more than 500 people were injured in the Oct. 1 mass shooting in Las Vegas.

The Red Cross helped out by providing 450 “blood products” to local hospitals.

“[The Las Vegas shooting] illustrates that it’s the blood already on the shelves that helps during an emergency,” the Red Cross said.

Those shelves did need to be replenished after the shooting. In response, people began showing up at donation centers.

“It’s their way of being able to do something instead of sitting around helplessly,” Dennis Todd, chair of the AABB Interorganizational Task Force on Domestic Disasters and Acts of Terrorism, told Newsweek.

However, more than enough people volunteered, and that has officials worried.

For starters, blood centers don’t have enough workers or time to process this overload.

There is also a storage issue.

Red Cross officials note that red blood cells can only be stored for 42 days before they have to be thrown out. Platelets only last five days.

A similar outpouring of blood donations was seen after the Sept. 11, 2001 terrorist attacks.

More than 500,000 units of whole blood were donated in the weeks after the attacks.

However, 200,000 units had to be tossed out when they became too old.

When that fact was reported, blood donations dropped off dramatically.

Blood officials are trying to avoid a repeat of that syndrome in the wake of the Las Vegas mass shooting.

Blood center officials say there is a shooting involving multiple victims virtually every day in the United States.

The Red Cross reports it responds to 64,000 disasters every year in the United States.

“To help ensure that the U.S. blood supply remains sufficient, the Task Force recommends that eligible donors contact their local blood donation center to schedule an appointment for the coming weeks and months,” the AABB said in a statement. “The Task Force thanks those who wish to help and encourages all eligible individuals to give blood regularly to help ensure that blood is available whenever and wherever it is needed.”

Those interested in donating can contact the following agencies.