Reference collection 660.03 E56 and incomplete 4th ed. Reference collection 660.03 E56.4 Includes much chemistry as well as chemical technology. Useful for common, industrial or environmental substances and topics. Often includes data, reactions, methods, environmental aspects, uses, safety. Has substantial bibliographies after articles often including reports and patents.
Index covers substance names, properties, topics but the indexing of substances can be erratic.
The 3rd edition has an index for all volumes at the end of the set. The 4th edition has indexes for every 4 volumes. Ullmann's encyclopedia of industrial chemistry. Section A covers chemicals, processes etc. Section B covers basic principles.