This is a picture of a Rampart General Pre-Cast chimney which had a significant portion of the chimney collapse after the heavy January rains.
These chimneys are made of concrete, even though they usually have a brick pattern. Visit www.luckysully.com for more information on these chimneys. There are tens of thousands of homes in Orange County with these chimneys. If you see any vertical cracking, it is important to get the repairs done immediately as the cracks will only expand. If the cracks are repaired quickly enough you can get many more years of use out of your fireplace. If you wait you may have to demolish and rebuild the entire chimney and fireplace. In this case, we could only recommend that the homeowner find someone to demolish the chimney and replace it.