In what may be the beginning of a long-anticipated consolidation of the chemical industry, Dow Chemical today said it was buying coatings and electronic-materials company Rohm & Haas in a $15.3 billion all-cash deal, reports the Wall Street Journal. Dow is backed by $3 billion from Warren Buffett's Berkshire Hathaway—the second time in past months that the Oracle of Omaha has assisted in a buyout. (More Dow Chemical Co. stories.)