A security checkpoint was closed for about 40 minutes at New York’s LaGuardia Airport after an alarm went off and agents found an unknown substance in a carry-on bag.

The Fire Department says three people have been taken to a hospital to be checked as a precaution on Wednesday morning.

Port Authority spokesman Joe Pentangelo says initial reports indicate it might have been some sort of “food substance.”

The Transportation Security Administration says the bag was inspected after an alarm went off at the checkpoint in Terminal B. It says Port Authority police were notified “out of an abundance of caution.”

The checkpoint was reopened at about 6:30 a.m.

(AP)