Yakima police said a series of mysterious Thursday night explosions in a Yakima neighborhood -- later determined to be caused a mixture of drain cleaners -- led to a resident reporting a suspicious device spotted in a neighborhood carport near a bush fire caused by the explosions, the Yakima Herald reported Tuesday.
Yakima police Lt. Nolan Wentz described the device as a small plastic water bottle wrapped with tape that appeared to have been left in the location for "quite some time."
The Washington State Patrol bomb squad moved the device to a nearby parking lot and detonated it, resulting in mercury being sprayed around the area.
U.S. Environmental Protection Agency investigators confirmed the presence of mercury in the area during the weekend and ordered the parking lot to be covered in hot asphalt.
"Any amount of mercury, which can spread into the air we breathe, poses a hazard," Parker said. "There is no safe amount of mercury if people are breathing in the vapor."
Police said they do not know why there was a bottle of mercury in the carport.
Investigators said they do not know the source of the mixed drain cleaners that triggered the explosions Thursday and police have not determined whether the explosions were intentional.