Capillaries. Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins).The primary function of capillaries is the exchange of materials between the blood and tissue cells.apillaries. Capillaries, the smallest and most numerous of the blood vessels, form the connection between the vessels that carry blood away from the heart (arteries) and the vessels that return blood to the heart (veins).
Class C Operator. Class C Operator of a UST facility is a person designated by the UST system owner who typically. controls the dispensing of fuel at the facility and is responsible for initial response to alarms, releases, spills, overfills or threats to the public or to the environment.
Chapter 1 â Operator Overview. This chapter describes the primary responsibilities of the Class A, Class B, and Class C operator. It also includes the training requirements for each class of operator. This chapter seeks to raise environmental awareness as well as clearly communicate a fundamental comprehension of UST systems.