diff --git a/bgzf.c b/bgzf.c
index 216cd04..62fb489 100644
--- a/bgzf.c
+++ b/bgzf.c
@@ -627,6 +627,9 @@ int bgzf_close(BGZF* fp)
     if (fp->open_mode == 'w') {
         if (bgzf_flush(fp) != 0) return -1;
 		{ // add an empty block
+			// add 28 bytes EOF empty block
+			fp->compress_level=Z_DEFAULT_COMPRESSION; //don't need value again
+			// (different compression levels would give different empty blocks)
 			int count, block_length = deflate_block(fp, 0);
 #ifdef _USE_KNETFILE
 			count = fwrite(fp->compressed_block, 1, block_length, fp->x.fpw);