Great question! I'm not an expert on lead specifically, but as with all other hazardous materials, it will be about looking at the most common routes to exposure (inhalation of dust, inadvertent ingestion from direct skin contact, or whatever) and mitigating those. Unfortunately, there's only so much you can do to reduce contact if you're actually conserving an object that contains lead: it generally requires you to spend hours and hours working in close proximity! Most of the time, it's a tremendous privilege to spend so much time caring for something ancient, but occasionally it can also be to the detriment of the conservator.
One of the problems with heritage conservation is that until recently it has been very overlooked and not afforded as much pay or status as other professions that require an equal amount of skill and education. As I said, it's a female-heavy profession, so I'm sure this is not a coincidence! And there's definitely a connection with the fact that it requires care and patience and empathy (see also nursing), which are seen as "feminine" attributes. Until recently, there has been a pervasive attitude that it's such a privilege to be doing the job at all that to ask for fair pay or working conditions - short-term contracts are rife - is a bit distasteful. It's a vocation, so conservators should be grateful to be paid at all! Luckily, this has changed a lot in the last 20 years - partly because we started to organise collectively, and partly because it became a more "sciency" profession, and therefore more "respectable" 
- but I think there are still comparisons to be made with how other "female" professions such as teaching and nursing have struggled to be respected.
Sorry, that's all a long way off the original topic, but still relevant to this board, I hope!