State officials requested that a slackline strung high in the trees behind Sunset Elementary School on Oahu’s North Shore be removed for safety purposes.

The twin lines were erected sometime in January in the Pupukea-Paumalu Forest Reserve behind Sunset Elementary — and caught the attention of media, social media and crowds when a man was spotted walking across one of them.

The state Department of Land and Natural Resources said no rules or laws appear to have been broken, but the lines pose a hazard to Honolulu Fire Department rescue operations.

HFD said in a statement that its flight operations for rescue-related emergencies are primarily at low altitude in valleys or on ridgelines.

“Unmarked wires or lines in the path of the rescue helicopter present a very serious hazard to search and rescue personnel that can result in injury or worse, death,” said HFD in a statement. “We would like to ask for the community’s assistance in keeping our personnel safe by not placing permanent or temporary wires or lines in areas that can affect search and rescue operations.”

Slacklining is a sport or art accomplished by stretching and tensioning a 1- to 2-inch-wide length of nylon/polyester webbing between two anchor points and balancing on it, according to Slackline U.S., a nonprofit.

It looks at first glance like tightrope walking, said Slackline U.S., but is a combination of “balance training, recreation, and a moving meditation.”

DLNR Division of Conservation and Resources Enforcement Chief Jason Redulla said this was a clear example of ” recreationalists not considering the impacts of their activities.”

“A pilot flying at low altitude may not have the time to maneuver fast enough to avoid a potential strike,” said Redulla in a news release. “Lines like these could not only impact HFD helicopters, but also military and tour aircraft. We really want to encourage slackliners and others to think through their actions, so as not to endanger lives.”