It says all seven crew members safely left the plane after the incident at 08:30 native time (22:30 GMT Wednesday) at Andersen Air Drive Base.
The US Air Drive instructed the BBC it was treating the incident as a “mishap”.
The bomber was deployed to the US island territory from North Dakota as a part of the army’s steady presence within the Pacific.
Native information web site Kuam quoted the Guam governor’s workplace as saying: “We guarantee the general public this doesn’t look like an assault.”
The crew members from the 69th Expeditionary Bomb Squadron have been on a routine coaching mission, the Air Drive mentioned in a press release.
It mentioned steps have been being taken to minimise the environmental affect, with out offering additional particulars.
B-52s are nonetheless going robust after 60 years in service within the US army – from Vietnam to Afghanistan.
Their important operate is to offer the US with instant standard and nuclear world strike functionality.
Guam is a US territory in Micronesia within the western Pacific, about 6,000km (3,700 miles) west of Hawaii.
The US Military’s bases there are thought-about among the many most strategically essential within the area.
In 2008, six crew members died when a B-52 crashed into the ocean close to Guam.