Following Colbert's edict of October 5, 1688, regulating the manufacture of Marseille soap, many soap factories were established in the area. In 1786, 49 factories produced 76,000 tons of soap in Marseille and employed 600 workers and an extra labor force of 1,500 convicts. In 1813, more than 60 manufactures used soda, produced chemically according to the Nicolas Leblanc process, and raw materials (palm, peanut, coconut, sesame oils) from Africa or the Middle East. Their number rose to 90 at the start of the 20th century when chemist François Merklen fixed the formula for Marseille soap. The difficulties of maritime transport at the time of the First World War seriously undermined the activity of the soap makers whose production decreased. While Marseille still provided half of France's soap production when World War II broke out, the product was quickly supplanted by synthetic detergents, and most of the soap factories closed.