This book provide an opportunity to microbiologist to understand the need of the hour and increase their research in a new area to understand the type of bacteria in relation with steel industries and further to provide biological solution and safeguard the environment. This is an insight on Contamination of coolants used in industries with tramp oil, microbes, metal pieces, etc., These contaminants makes them loose their coolant property considerably with time, resulting in a product which is hazardous to the environment. Despite the advances in technology for the control of coolant contamination, bacterial contamination appears to be still a major concern.