The 12 superphosphate works, located mainly near ports, produce about a million tons of fertiliser a year. The industry uses rock phosphate from Ocean and Nauru Islands and sulphuric acid manufactured from imported sulphur. Some superphosphate is compounded with trace elements; some, again, is made into pellets for aerial topdressing. Twenty-five manufacturers of paint and varnish supply New Zealand's main needs. Most of the output of £6.8 million comes from firms in Auckland and Wellington. Factories in Petone account for much of the soap production of £3.4 million. The soap industry also produces candles and recovers crude glycerine. Pharmaceutical preparations, toilet goods, and cosmetics, valued at £4.6 million, are made in the main centres, where many other items are manufactured for farm, household, and industrial use.