Federal and state regulators say Smitty’s Supply ignored pollution laws for years before an August explosion in Roseland spilled oil into the Tangipahoa River.

Authorities say they've arrested two Massachusetts men in connection with a weekend explosion at Harvard Medical School.

At least 13 people were killed and several others injured after a UPS plane crashed shortly after taking off from the Louisville International Airport on Tuesday.

The explosion occurred early Saturday on the fourth floor of Harvard Medical School's Goldenson Building. No one was injured. The building houses labs and offices associated with the school’s neurobiology department.

Columbus Division of Fire Battalion Chief Jeffrey Geitter said that crews were on scene prior to the explosion on a report of a natural gas leak. He said that while the crews were investigating, there was an explosion that resulted in a fire and a portion of the building collapsing.

An explosion at a Mississippi chemical plant caused an ammonia leak, forced nearby residents to evacuate, officials said, and sent a giant plume of yellowish smoke into the air.