After the questionable early experiments there, management was given over to Columbia University, who had combined goals of research, education, and public outreach, but after about 8 years decided it was too expensive. They built dorms and had a semester residential program for students, as well as opening it to the public. It was not maintained as an entirely sealed environment.

The original owners sold it to a development company that has had plans for homebuilding, etc. on some of the property, but currently it's under the management of the University of Arizona. The UA has similar plans to Columbia's, but it should probably have an easier time of managing it locally, instead of cross-country. Ed Bass, the original finiancier of the place is still involved, supporting the university's work.

Here's the UA web site: click.

I went on a tour a few years ago and it was pretty interesting. There are certainly an assortment of scientific projects that can be carried out there in its relatively controlled environment, without the requirement for things to be totally sealed.

~ Becky in Tucson
(and UA employee)