Keep sanding to a mininum and wear a protective mask. The dust is hazardous if breathed in by nose or mouth.
All loose paint chips must be removed. Small children are especially suceptible to health risks from swallowing lead-based paint chips.
Handling items coated with lead-based paint and then putting your hands near or in your mouth is a concern.
Whenever I repurpose old window shutters of frames like the ones pictured, I apply a coat of polyurethane or shellac over it, so that there is no lead based paint exposed. This also solves nearly all of the problems associated with lead-based paint chips falling off onto the floor after it is hung.
Hazards of coming into contact with lead-based paints include, high blood pressure, headaches, nausea, brain damage, and slow growth in children. Most homes built before 1978 contain it. Many of us still live in older homes, so there are specific ways to deal with it, according to the United States Evironmental Protection Agency.
Here is their link for more information.
Please be careful when you suspect that something you are working with is a canidate for lead-based-paint, such as architectural moldings, banister railings and posts, old fencing, metal ceiling tiles, etc.
Keep up the good work.