That's because a literal trash fire at the Salt River Landfill sent plumes of black smoke billowing into the sky over the weekend. Spontaneous combustion triggered flames on Saturday at the 200-acre landfill, which is part of the Salt River Indian Reservation about 20 miles east of Phoenix.
Landfill crews responded quickly to the fire, according to Martin Harvier, president of the Salt River Pima-Maricopa Indian Community.
Harvier said the flames started in a landfill full of green waste, which is nontoxic materials such as leaves, tree branches, grass and unpainted, untreated lumber.
Firefighters from the Salt River Fire Department, public works crews from the reservation and waste contractors worked around the clock to separate the inferno into three manageable blazes so water trucks could slip in to tame the flames, Harvier said.
"The remaining two piles are very well contained," he said Wednesday in a Facebook post. "Currently, there are no open flames."
By Thursday, firefighters had fully extinguished one of the three fires, Harvier said. Now, their priority is to stop the smoldering and snuff out the smoke on the two remaining fires.
"Our teams are fully committed to the safety and well-being of our community and the residents of our neighboring municipalities," Harvier said.
The landfill serves Gilbert, Mesa and Scottsdale, as well as the Salt River Pima-Maricopa and Fort McDowell Yavapai communities.
When will Phoenix landfill fire smell go away?
Harvier said officials currently are monitoring air quality within and near the Salt River community. The tribe also provides hourly updates on its official website.
Until the air is cleared of any lingering smoke, though, Harvier urged the public to take precautions. That means staying inside, closing windows and doors, wearing face masks and using air purifiers if they are available. Also, limit the amount of time you spend outside, Harvier said.
Officials don't yet know when the lingering landfill fire smell will finally clear out.
The smoky stench is an extra punch to Maricopa County's air quality, which earned an F grade in the American Lung Association's 2023 State of the Air report.
"The Salt River landfill fire is still smoldering," the Arizona Department of Environmental Quality said on Wednesday.
The agency said the state's Air Quality Index monitors were in the "good" category.
"If you're seeing/smelling smoke, and are sensitive, limit outdoor activity," ADEQ said on X, formerly known as Twitter. "Easterly winds in the coming days should clear any remaining smoke."