You could try putting the string into an array and then outputting it with an echo.
Something like
$breakdown = explode(',', $row_User['BOMString']);
for ($countx = 0; $countx < count($breakdown); $count++)
{
echo $breakdown[$countx] . '<br />';
}
I have just typed this off the cuff, and not actually tested it but the theory should work.
Cheers
Ian