Single-use laundry detergent pods have become popular since their introduction two years ago.

But the colorful disks can easily be mistaken for candy by children. And that could be life-threatening.

Investigators from North Carolina’s state poison center, headquartered at Carolinas Medical Center in Charlotte, were instrumental in identifying the danger.

In May, the center took calls about two children who became suddenly and critically ill after ingesting some of the laundry detergent pods.

The first child, a 20-month-old boy, began vomiting uncontrollably within 10 minutes, then became extremely lethargic, experienced difficulty breathing and required ventilator support. But his health improved quickly, and he was discharged from the hospital 36 hours later.

The second child, 15 months, had similar symptoms, received similar treatment and was discharged 24 hours later.

It wasn’t unexpected that the children would become ill, but the recovery path was unusual, said Dr. Michael Beuhler, medical director of Carolinas Poison Center.

“Kids get sick from detergents. Just not like this.”

Typically, children who would get sick enough to require a ventilator would suffer “significant lung injury” and a “long, rocky course” in the intensive care unit.

But when these children woke up, “they were just fine, which is weird,” Beuhler said.

Their outcomes might not have been so good if the parents hadn’t called quickly for emergency medical assistance.

But health officials still have questions about the cases, which were described in an October publication by the Centers for Disease Control and Prevention.

Beuhler suspected a contaminant, such as in 2007, when children became comatose after swallowing Aqua Dots bead toys. The toys were found to contain a chemical that metabolized into the toxic “date rape” drug called GHB.

But laboratory tests ruled out any contaminant in the detergent pods.

“Nothing we’ve tested for has shown up,” Beuhler said. “We know that it’s not allergic. We know it’s not the fragrance. We know it’s not caustic. We don’t think it’s the alcohol.”

For now, the focus is on “a sedative effect of the detergent itself,” he said.

He advises parents to keep the pods away from children. Some manufacturers have added warnings and made packages harder to open.

“These pods should be treated with respect and used as directed,” Beuhler said. “This isn’t like normal laundry detergent. It’s super concentrated. It will melt and release its contents when it gets wet.”

If children do take a bite from the pods, adults should call for help immediately.

“Wipe off their mouth, pick up the phone, and call the poison center,” Beuhler said. “A lot of them do fine, but there’s a small minority that become very sick very quickly. And when they do it’s frightening.”