Firstly, the people featured in the article are not making stained glass: they're specialist conservators who are carrying out remedial treatments and care for very fragile, very valuable medieval stained glass. I used to work in a very similar area myself and I know several people who work in this field: it's not something the Job Centre would send you to do
and many of the conservators working there will have postgraduate-level training.
Health and safety in heritage conservation is taken very seriously as it often involves using chemicals, use of x-radiography or being exposed to other hazards such as moulds or toxic pesticides used to treat objects decades ago. Conservators routinely use PPE and take other appropriate mitigation measures such as working under extraction where possible. I am certain that the people working at YGT will be protected as much as possible - indeed, it's clear that they're already having regular blood tests to monitor their lead exposure.
I lurk on this board a lot (and post occasionally), but it's disappointing to see so many wrong-headed reactions to this story. The "sex and gender" angle to this story, IMO, is not so much that women are being treated differently from men in terms of occupational hazard exposure (after all, they have different biology...), or whether women can identify our of these limits, but that heritage conservation is an overwhelmingly female profession (around 65-70% of conservators are women, and the rates are much higher in some specialisms). If you stop employing women because you can't mitigate their risk of lead exposure, then you will soon find that you are unable to employ enough stained glass conservators, full stop.