If you have rust spots, you can prep the rusted areas down to bare steel, and then use a corrosion-inhibiting spot primer. There are moisture-cured urethanes with zinc pigment. There are also epoxy materials with inhibitors in them. If a barrier is breached, these work. No, said Kline.
Breaches come from mechanical damage.
Kline has some final advice for painters like the fellow who paints New York warehouses. Sometimes it's white. Before you assume something is not lead paint, check it out. Inexpensive check kits are available. If there's lead there, you need to protect the workers and the environment appropriately.