密件抄送不与邮件附件结合使用

Can anybody tell me why the Bcc is not working? There is something I am doing wrong can't seam to figure it out. Also I would like to know if I can add multiple Bcc mail addresses in this way.

$headers .="Bcc: email address1
";
$headers .="Bcc: email address2
";

mail code

$semi_rand = md5(time());
$mime_boundary = "==Multipart_Boundary_x{$semi_rand}x";
$headers="From:test<$email_from>
"; // Who the email is from (example)
$headers.="Bcc:test@test.com
";
$headers.= "
MIME-Version: 1.0
" .
"Content-Type: multipart/mixed;
" .
" boundary=\"{$mime_boundary}\"";
$email_message .= "This is a multi-part message in MIME format.

" .
"--{$mime_boundary}
" .
"Content-Type:text/html; charset=\"iso-8859-1\"
" .
"Content-Transfer-Encoding: 7bit

" . $email_txt;
$email_message .= "

";
$data = chunk_split(base64_encode($data));
$email_message .= "--{$mime_boundary}
" .
"Content-Type: {$fileatt_type};
" .
" name=\"{$fileatt_name}\"
" .
"Content-Transfer-Encoding: base64

" .
$data . "

" .
"--{$mime_boundary}--
";

mail($email_to,$email_subject,$email_message,$headers);`