TORONTO - Two people have been charged with mischief after a London, Ont., apartment building was evacuated Thursday following a chemical spill.

Police say a 24-year-old woman and a 15-year-old boy specifically targeted the building because of a dispute with property management.

Police say the spill was not a random act, and could be considered a prank gone "horribly wrong.''

A combination of regular household items was used to concoct the substance, but the Middlesex London Health Unit says it don't expect those exposed to the spill will suffer any long-term health problems.

Police say damage to the building is expected to exceed $50,000.