Coal is formed when peat is altered physically and chemically. This process is called coalification.. During coalification, peat undergoes several changes as a result of bacterial decay, compaction, heat, and time.
On January 9, 2011, ABC Family announced the show would return for its fourth season on March 26, 2011. On February 2, 2012, ABC Family renewed the series for a fifth season. On October 9, 2012, it was announced that the fifth season of The Secret Life of the American Teenager would be the final season. The series finale aired on June 3, 2013.
This led to the production of a seventh season, Hoarders: Family Secrets, which aired on Lifetime from May 28, 2015 to July 30, 2015. The program returned to A&E for an eighth season which began January 3, 2016. A second part of the eighth season began on August 21, 2016, under the title: Hoarders: Then and Now.