Applications of fiber optic sensors in the power generation, chemical process, and steel making industries are discussed. Emphasis is placed on the special needs and requirements in these industries and how optical sensors can uniquely satisfy these needs. Fiber optic sensors are described which make direct measurements of quantities that heretofore could be made only indirectly using conventional sensing methods. Limitations of optical sensors along with their own special application requirements in industry are also discussed. Specific Babcock & Wilcox fiber optic sensors and systems are described which have been developed or are currently under development.