What is the history of the Maltese Cross used by firefighters?

The Maltese Cross is derived from the emblem of the medieval military order of Saint John of Jerusalem, also known as the Knights Hospitaller who originally ran a hospital in Jerusalem for pilgrims to the Holy Land and then became their protectors. Their emblem was a white cross on a red field.
There is a popular story concerning the connection between the Knights of Malta and fire fighters: The Knights of Saint John of Jerusalem (later known as the Knights of Malta) fought in the First Crusade against the Saracen. The Saracen used a novel and terrifying weapon consisting of glass containers full of a flammable mixture of naphtha. During a siege by the Crusaders, the Saracen would throw these onto the besiegers which would saturate them with this highly flammable liquid, at which time the Saracen would throw a torch into the midst of the Crusaders, setting them on fire. The Knights of St. John took it upon themselves to pull the Crusaders to safety, put out their flames and treat their injuries. Because of their selfless heroics, the Maltese cross has come to symbolize a willingness and commitment to brave danger in order to rescue others from a fiery death.
After the loss of the Holy land, the order established a base on the Island of Malta where in the 16th Century their symbol was redesigned as 4 white arrowheads arranged in the shape of a cross on a red field and the order came to be known as the Knights of Malta.

After being ejected from the island by Napoleon in 1798 the Knights reformed as a worldwide aid organization, providing first aid training, first aid services and emergency medical services to the victims of natural disasters, epidemics and armed conflicts.
A modified form of the Maltese Cross has been adopted by virtually all Firefighters of the United States and Canada and is used by the International Association of Fire Fighters. This cross resembles the original Maltese cross with its eight outer points but has been modified by the inclusion of a central circle and bending out the V-shape between these points to follow the shape of the inner circle.

To the original Knights of Malta the eight points outer points stood for:
Loyalty
Piety
Generosity
Bravery
Glory and honor
Contempt of death
Helpfulness towards the poor and the sick
Respect for the church.

To the modern organization of the Knights of Malta the points stand for :
Observant
Tactful
Resourceful
Dexterous
Explicit
Discriminating
Persevering
Sympathetic

To a Fire Fighter the points stand for:
Perseverance
Loyalty
Dexterity
Explicitness
Observation
Tact
Sympathy
Gallantry