Detectives have today appealed for information after the offence which took place between 6pm and 7.30pm on Tuesday at the at Lupset Health Centre on George-a-Green Court.
It was discovered after cleaning staff found fire damage from an already extinguished blaze in a male toilet cubicle.
Fire service investigators and police were called and it is believed the fire was started deliberately.
Anyone who has information about the fire is asked to contact DS Sam Freeman at Wakefield District CID on 101 referencing police crime number 13180220767.
Information also be given anonymously to the independent Crimestoppers charity on 0800 555 111.