A marker system including at least one sensor configured to be positioned relative to a container to obtain information regarding content within the container, and a control module which receives the sensed information. Based on the sensed information, the system determines if the content of the container is approved for use for the particular application and/or equipment. By way of example, the information being sensed can be a marker chemical added to the content of the container, an ingredient in the container, or information read from outside the container.
