I have a free open-source add-in that can grab that information  for
you.
For example, if the Social Security number  is in cell A1, these three
formula would get you the name, birth date, and death date listed for it:

=RCHGetTableCell("http://ssdi.rootsweb.com/cgi-bin/ssdi.cgi?ssn="&A1,1,"Record?"\
,,,,1)
=RCHGetTableCell("http://ssdi.rootsweb.com/cgi-bin/ssdi.cgi?ssn="&A1,2,"Record?"\
,,,,1)
=RCHGetTableCell("http://ssdi.rootsweb.com/cgi-bin/ssdi.cgi?ssn="&A1,3,"Record?"\
,,,,1)

For example, that last formula says to:

1. Grab the source code of web  page:

"http://ssdi.rootsweb.com/cgi-bin/ssdi.cgi?ssn="&A1

2. Look for "Record?" within that source code (the header line of the
table).

3. The "1" parameter at the end says to skip to the next line of the
table.

4. The "3" parameter says to pick up the 3rd table cell on that row of
the table.

Note that the other two formula just vary in the parameter that says
which cell of the table row to pick up. So you could easily pick up
the other columns of that table row by just changing that value.