Bomb disposal officers are attending the scene to make an assessment.
In an email to members leaked to Granada Reports, the Federation warns it "is an unsafe system" creating "unacceptable risks".
Shukri Yahya Abdi was reported missing by her mother just after 7.30pm on June 27.
The two week campaign saw 140 firearms handed in during the armistice.
Hadeer Jamil Alonazi, 26, from Rusholme, South Manchester was last seen on July 2.
Sarah Rogers joined a special police force operation running over the summer months to bring those carrying knives to justice.
A teenage girl has been found dead in woodland in Greater Manchester.
None of the youths suffered long-term health effects, but medics have issued a warning to avoid buying or using "THC vape".
Chief Constable, Ian Hopkins, has apologised for the failings of his officers which resulted in the death of Anthony Grainger in 2012.
The shooting happened shortly before 11.30am today near to Outline Health & Fitness Centre on Lever Street.