Forest Ong sent me the below information obtained from his internet search.
Olive for cooking has been known as good for health.
But be careful! There are different levels of quality. Just look the labels on the bottles.
If the bottle is labeled "Extra Virgin", the product is super! It was made with the first time oil squeezed out from olives and is good for all ways of cooking and salad mixture.
If it is labeled "pure", that was the second or third time squeezed out oil and is good for all cooking but not for mixing salad.
If it is labeled "olive oil' or "macro olive oil", it is the 4th or 5th time using heat to squeeze out oil. These are cheaper but can cause cancers. They can only be used in industry.