Either way, Perl spawns a system call. You'll have to untaint a couple of things in %ENV. For example, this fails:

#!/usr/bin/perl -wT
use strict;

# delete $ENV{qw( BASH_ENV PATH )};

my $output = `/bin/ls`;
print "Output is ($output)\n";
[download]

Uncommenting the appropriate line makes it work, at least on my box. Depending on what's tainted, you may have to do a little more work.