Tennessee explosives plant blast that killed 16 was chain reaction felt 20 miles away

By JONATHAN MATTISE  and KRISTIN M. HALL  Associated Press McEWEN, Tenn. (AP) — A massive blast at a Tennessee explosives plant that killed 16 people, leveled the building and was felt more than 20 miles away began in an area where workers used kettles to produce a mixture of explosives and set off other explosives…