The building was surrounded by vegetation on fire when a team of “helitack” firefighters arrived to protect the area on Tuesday. Grand Canyon National Park officials said the crews knew if the pump house fell, the consequences could cripple park operations for months.

A new report has calculated that making national parks the responsibility of states would raise costs, cut revenue and reduce access for Arizonans.

A wildfire that tore through a historic Grand Canyon Lodge​ had been allowed to burn for days before erupting over the weekend, raising questions about federal officials' decision not to aggressively attack it right away.