It is likely the paints have included lead over the years. This would pose some risks in certain stripping methods and it is important to collect and dispose of scrapings. Scrape off any loose paint and try a good quality oil based primer and compatible finish coat on a small area to test adhesion. I would avoid stripping paint unless there is just no other way. Talk to a representative at a pro paint store like Benjamin Moore. They may be be of assistance to you in finding the best product and will back up their product against failures like this.