diff --git a/src/bigWiggleReader.c b/src/bigWiggleReader.c
index 2983771..92bccc0 100644
--- a/src/bigWiggleReader.c
+++ b/src/bigWiggleReader.c
@@ -21,6 +21,7 @@ bool readBigWigBuffer(BigFileReaderData * data) {
 	double value;
 	char *blockPt = data->uncompressBuf;
 	struct bwgSectionHead head;
+	start = finish = 0;
 	
 	bwgSectionHeadFromMem(&(blockPt), &(head), data->isSwapped);