sheltered workshop

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A workplace that provides a supportive environment where physically or mentally challenged persons can acquire job skills and vocational experience.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a place where persons with limited mental ability can work in a safe environment.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a workshop that offers jobs to members of the physically or developmentally disabled population