Replaces the default output with the to_chat wrapper.

code/game/objects/effects/effect_system/effects_foam.dm

@@ -220,7 +220,7 @@
 /obj/structure/foamedmetal/attack_hand(mob/user)
 	user.changeNext_move(CLICK_CD_MELEE)
 	user.do_attack_animation(src, ATTACK_EFFECT_PUNCH)
-	user << "<span class='warning'>You hit the metal foam but bounce off it!</span>"
+	to_chat(user, "<span class='warning'>You hit the metal foam but bounce off it!</span>")
 	playsound(src.loc, 'sound/weapons/tap.ogg', 100, 1)
 
 /obj/structure/foamedmetal/CanPass(atom/movable/mover, turf/target, height=1.5)

code/game/objects/effects/effect_system/effects_other.dm

@@ -130,7 +130,7 @@
 
 		for(var/mob/M in viewers(1, location))
 			if (prob (50 * amount))
-				M << "<span class='danger'>The explosion knocks you down.</span>"
+				to_chat(M, "<span class='danger'>The explosion knocks you down.</span>")
 				M.Weaken(rand(1,5))
 		return
 	else