Why is the US government planning for ‘mass fatalities’ ?

Why is the US government planning for ‘mass fatalities’ ?

 Late last week, a bill HR 6566 was introduced on the floor of the US House of Representatives. I couldn’t believe my eyes when I read it.
The bill is entitled the “Mass Fatality Planning and Religious Considerations Act,” and its stated purpose is “[to] amend the Homeland Security Act of 2002 to require the Administrator of the Federal Emergency Management Agency to provide guidance and coordination for mass fatality planning…”