responders

/R IH0 S P AA1 N D ER0 Z/
noun
  1. 1

    One who responds.

  2. 2

    A person who responds to an emergency situation or other summons.

    โ€œ911 responders arrived at the scene within five minutes after the call.โ€

Source: https://en.wiktionary.org/wiki/responder, https://en.wiktionary.org/wiki/responders