1991 Jeep Cherokee heater is blowing steam/smoke?

[10 pts for me?]

Can anyone give me an idea of why this is happening? When I turn my heat on it blows smoke/steam and fogs up the windows. It's been leaving a white residue. When the heat is off there is still that steam/smoke coming out of the vents. It does not matter if I have the defrost or the regular heat on and it smells. Any ideas of what this could be? Thank you!

 

[oliver_a2002]

Heater core or hoses are leaking.

 

[Jcontrols]

Your heater coil has ruptured! Get it replaced ASAP! You don't really want to be breathing that ethylene glycol(anti-freeze)do you? ;-(=