What would be causing a silicone like smell to be coming from the A/C in my car?

It is not present in the engine compartment and is strongest when the A/C is first turned on. It fades as the A/C is running. The car is a 91 Olds 88.

What would be causing a silicone like smell to be coming from the A/C in my car?
you sure that isn't an antifreeze smell? Sounds like a pin-hole in the heater core.
Reply:there is no silicone that could leak from any component, so the smell has to be mildew, coolant as the previous answer mentioned, or maybe refrigerant oil is leaking from the evaporator. check for any presence of fluid at the bottom of the heater case, and the drain in the firewall. if nothing is found, try spraying lysol into the fresh air vents with the air set to fresh, running on low speed. that will nuke any odors not caused by a leak.
Reply:The smell is a small leak in your heater core. What you are smelling is anti-freeze.