Enviroplan was started as an environmental consulting firm in the early 1970's by Dr. Howard Ellis.  The firm was based in New Jersey and in the 1980's it started a small group in Indianapolis to put together automated equipment to monitor smoke stack emissions.  The technology used dried air to retrieve a diluted sample from the smoke stream within the stack.  The sample was returned to the base of the stack and fed into various gas analyzers for continuous monitoring.  With the advent of new regulations of the clean air act, Enviroplan expanded the group and provided well over a hundred monitoring systems to power companies across the nation.  After the boom faded, the company went bankrupt in 1994.  At it's height, Enviroplan employed about 150 people.