Jim Brennan, a senior consulting scientist with Arch Chemicals, died on Oct. 21 in Nashville. He was 70.

“He was truly one of the clear geniuses of the organization,” said John Puetz, director of technology at Arch. “Jim was absolutely brilliant, but never flaunted it. His interests were never self-seeking. They were always for the betterment of the industry.”

Born in St. Louis on Aug. 13, 1941, Brennan received Bachelor’s and Master’s degrees in chemistry from Saint Louis University, and a Ph.D. in inorganic chemistry from Indiana University — Bloomington in 1973. That same year, he moved to Connecticut, where he began a 38-year career with Olin Industries, which later became Arch Chemicals. He relocated to Chattanooga, Tenn., in 2000.

During the late 1970s and early ’80s, Brennan chaired NSPI’s Chemical Treatment and Process Committee (the precursor to APSP’s Recreational Water Quality Committee). Under his guidance, the committee provided the first chemical standards guidelines for the industry. He also was a member of  NSPI’s Technical Council (now APSP’s Technical Committee) and served on a variety of National Sanitation Foundation committees.

Besides his reputation for meticulous research, Brennan had a lighter side as well — he enjoyed golfing, listening to his iPod and playing country western music on his guitar.

Funeral services were held on Oct. 24 in Chattanooga. Brennan is survived by his wife, Patti, three sons and four grandchildren.