There's no way as an AP resident that you can avoid formalin entirely. To limit exposure, I would suggest you use appropriate PPE appropriately, periodically check that your grossing station's ventilation is working properly, and if a spill occurs, arrange for someone else to clean it up while you wait in another room for the air to clear. Also keep your face clear and hold your breath when opening large buckets or disposing of formalin. In my residency program, we were also somewhat concerned with xylene exposure in our frozen room, which had exceptionally poor ventilation. We had our hospital's occupational health experts check the air quality and they deemed it acceptable (but who knows). Lots of xylene in the histology lab so stay out of there if you can avoid it.