I recently had my chimney cleaned and was informed I have a hole in the side of the chimney. I checked and found the exhaust is from my kitchen stove. It is vented into the chimney.. I have lived in the house for 35 years and have fires often in the winter, I have had several chimney sweeps clean over the years and know one ever mentioned this vent...I believe the exhaust vent was put in when the house was built. By the way, the chimney sweep said the chimney otherwise looks good...Is this a real concern? What are my options?