Help for spray-painted ducts

I am having today installation of new duct work. They have spray-painted black the entrances to the duct vents. It is an oil base paint for heat up to 212. Does anyone see any toxic issues with this. I am not concerned about the first few days of curing, but the period of use of heat flowing over these vents in the next few years.
I also had at the cost of $600 a allergy-type system for allergy problems, so I had previuosly expressed my concern over these problems and was dismayed when they started installing the second floor and saw that they had spray-painted the vents. The other floor (a separate system) has already been completed.
Can anyone give advise. Thanks.
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