Editing to add information:
http://www.cis.org/articles/2004/fiscalexec.html - this is from 04. I'll keep digging around to see what fact and what is fiction.
http://www.reuters.com/article/healthNews/idUSN1346120320070313. Claims it's around 1%.
http://info.dhhs.state.nc.us/olm/manuals/dma/fcm/adm/MA_AL19-03.htm
SOCIAL SECURITY NUMBERS
Existing enumeration policies in the Medicaid, Food Stamps and Work First programs require all members of the assistance unit to provide their social security number (SSN) or apply for a SSN to be eligible for assistance. (See MA-3355, Enumeration Procedures, in the Family and Children’s Medicaid manual, MA-2450, Enumeration Procedures, in the Aged, Blind, and Disabled Medicaid manual, WF-110, Rule to Apply for a Social Security Number, in the Work First manual and FS-235, Social Security Enumeration, in the Food Stamp manual.) Benefits cannot be provided to a household member who does not provide his/her SSN. Other household members who provide their SSNs receive benefits, if otherwise eligible.
Under Medicaid policy, a household member who is not applying for assistance for him or herself is not considered a “member of the assistance unit” and is not required to provide his or her SSN. For example, a mother who is applying for Medicaid for her children only, cannot be required to provide her SSN.
If an applicant fails to provide a SSN, he cannot be included on the case. However, if he is financially responsible for an assistance unit member his income and resources must be counted when determining eligibility and benefit levels for the case.
A non-assistance unit member who is applying for assistance for another is not required to provide his SSN even if he has financial responsibility for an assistance unit member. For example, an ineligible parent who is applying for his/her eligible children only, cannot be required to provide his/her SSN.
You must inform individuals that SSNs will be used to verify employment/income and for other reasons related to the administration of the programs. Be sure to inform individuals that SSNs will not be shared with the Immigration and Naturalization Service (INS).
Applicants for emergency Medicaid do not have to provide their SSN.
CITIZENSHIP AND IMMIGRATION STATUS
A alien who does not meet the specific requirements of a qualified alien is a non-qualified alien and ineligible to receive assistance except for emergency Medicaid. Individuals who chooses not to provide information regarding their citizenship will not be included in the case and will not receive benefits, but other household members who do provide proof of their immigration status can still receive benefits, if otherwise eligible.
Applicants for emergency Medicaid are not required to provide information regarding their citizenship or immigration status.
There are limits on what an illegal alien qualifies for but they do and can qualify for some minimal state benefits these are older sources '03 and '04.
I'm sure there's more out there.
One more and goes indepth about Emergency Medicaid - it's in PDF format found on google and I don't know how to post it here but look for: Immigrant Access to Health Benefits.
I just copied and pasted the search result:
Immigrant Access to Health Benefits
File Format: PDF/Adobe Acrobat - View as HTML
every immigrant’s qualifications to receive benefits under PRWORA. ...... income families remain eligible for Medicaid after repeal of the AFDC. program. ...
www.accessproject.org/downloads/Immigrant_Access.pdf