As families huddle around campfires this summer, there's a product officials warn Minnesotans to use with caution: flame colorants.

If used correctly, the packets of crystalline powder turn normal flames iridescent. But confusing packaging has led some to open the packets and swallow the contents instead of throwing them into the fire, causing severe chemical burns, according to the Minnesota Poison Control System.

Poison Control officials prepared a report for the U.S. Consumer Product Safety Commission asking the federal agency to issue warnings about the products.

In early June, Poison Control received five calls related to products such as Mystical Fire and Magical Flames. The calls included the cases of three children and two adults who ingested the product within a few weeks of each other. That's a tiny fraction of Poison Control's annual 50,000 calls, but the timing and severity of the injuries caught the agency's attention.

"We're a small group answering phones on behalf of the public," said Dr. Travis Olives, associate medical director with Minnesota Poison Control. "So when we get four or five of these over the course of several weeks, we pick up on that."

Some people accidentally swallowed the products after opening the packet with their teeth or mistook them for candy or drink mixes. Olives said the black packaging and bright powder inside look very similar to Pop Rocks candy.

The products use copper sulfate to color flames, but that caustic material can cause chemical burns, internal bleeding or even death if the 0.8-ounce packet is ingested.

Although the packages bear warnings, Olives said the contents are still too easily accessible, especially to children.

"Kids are built to get into things, and they're good at it," he said. "And so I wouldn't put anything past a child, even if it did have a foul taste."

Jenna Albert, spokeswoman for Evergreen Research and Marketing, LLC, which makes Magical Flames, said the company will re-evaluate its product's safety but believes it already does a good job. The packaging has numerous warnings and is sealed with thick plastic that's not meant to be opened.

"We certainly do and have taken extensive measures to make this packaging safe for our consumers," Albert said.

A representative for Mystical Flames could not be reached.

U.S. Sen. Amy Klobuchar, D-Minn., also has spoken out. "I urge you to evaluate the packaging and work with manufacturers to ensure that it adequately prevents children from accessing its contents," she wrote in a letter to the Consumer Product Safety Commission on Tuesday.

Olives said misuse of the flame colorants isn't new or widespread.

"We don't see them very often," he said. "But when we do, they can be really, really bad."

Chris Bowling • 612-673-4434