It is illegal in Ohio, under ORC 2917.31, where it is called "Inducing panic". The law starts:
(A) No person shall cause the evacuation of any public place, or
otherwise cause serious public inconvenience or alarm, by doing any of
(1) Initiating or circulating a report or warning of an alleged or
impending fire, explosion, crime, or other catastrophe, knowing that
such report or warning is false;
Notice that the prohibited act is "caus[ing] the evacuation of any public place, or otherwise caus[ing] serious public inconvenience or alarm". Disorderly conduct, ORC 2917.11, has a lower and more general threshold:
No person shall recklessly cause inconvenience, annoyance, or alarm to
by doing various things by fighting, threatening, insulting, making loud noises, which also includes
(5) Creating a condition that is physically offensive to persons or
that presents a risk of physical harm to persons or property, by any
act that serves no lawful and reasonable purpose of the offender.
Note that if the act presents a risk of harm, it is prohibited.
Washington's law, RCW 9A.84.040 (False Reporting), does not require evacuation or harm to actually result.
A person is guilty of false reporting if with knowledge that the
information reported, conveyed, or circulated is false, he or she
initiates or circulates a false report or warning of an alleged
occurrence or impending occurrence of a fire, explosion, crime,
catastrophe, or emergency knowing that such false report is likely to
cause evacuation of a building, place of assembly, or transportation
facility, or to cause public inconvenience or alarm.
There is another law that would cover fire-shouting, RCW 9.40.100, which says
Any person... who willfully and without having reasonable grounds for
believing a fire exists, sends, gives, transmits, or sounds any false
alarm of fire, by shouting in a public place or by means of any public
or private fire alarm system or signal, or by telephone, is guilty of
In California, per Cal. Pen. 148.4(a)(2) a person is a violator if he
Willfully and maliciously sends, gives, transmits, or sounds any false
alarm of fire, by means of any fire alarm system or signal or by any
other means or methods.
It is likely that there is some such law in every state, though the specifics will vary.