Toxic heavy metals in Art Museums...

I've just submitted a comment to http://bit.ly/bGozSa, The Art Newspaper online in its commentary section regarding loosening standards on relative humidity restrictions within art museums worldwide. There is a movement within the museum community to lessen restrictions on the range of relative humidity, RH, of there climate control systems. The debate is whether the preventative costs taken conserving energy used to keep tight temperature ranges will out weigh the conservation of art work costs. My comment was directed to relative humidity restricting the amount of airborn release of the toxic materials, lead, mercury, cadmium, etc within the museums themselves. I went on to question why the EPA spends millions of dollars to remove these toxic metals from office buildings, libraries, schools, dwellings, etc. and to my knowledge has never addressed the fact that museums are filled with artifacts containing these materials. Why is that?, or, perhaps the EPA does address it and I am just not knowledgeble of that fact.