| 2013 | Chemson becomes part of the Turkish OYAK Group. Together with Akdeniz, also a member of the OYAK Group, Chemson becomes world market leader for PVC stabilisers. |
| 2008 | The Chemson Group is taken over by a mid-tier investment company. |
| 2004 | Chemson GmbH Frankfurt takes over the Allstab Chemicals Group. This takeover makes the Chemson Group the leading European provider of solid stabilisers for PVC processing. |
| 2003 | Chemson Ltda., Durox Ltda. and Penos S. A. bundle their lead oxide activities within Durox Ltda. in Rio Claro/Brazil. |
| 2001 | Chemson enters the Chinese market with the foundation of Dalian Chemson Chemical Products Co. Ltd. in Dalian/China. |
| 2000 | In April 2000, a private group of investors and management take over the Chemson Group as part of a management buy-out. Chemson Polymer Additive AG is founded in Arnoldstein/Austria. As part of this development, Chemetall moves the stabiliser business of its Brazilian subsidiary Chemetall do Brasil to the new company. Also in 2000, Chemson takes over the remaining shares of the Chemical Group and founds the joint venture Durox Ltda. with its headquarters in Rio Claro/Brazil together with two other partners. Durox Ltda. unites the lead oxide activities of the three companies in South America. |
| 1998 | Chemson buys shares in the Chemical Group. |
| 1996 | The US-American Chemical Group begins to manufacture PVC stabilisers at its Philadelphia site. |
| 1993 | The stabiliser activities of BBU and Cookson are bundled within the Chemson Group. |
| 1990 | Chemson purchases the remaining shares of BBU and the Cookson community shares. |
| 1989 | The Metallgesellschaft takes over the majority interests of the chemical business of the Bleiberger Bergwersunion (BBU). |
| 1986 | Stabiliser manufacturers Chemetall and Cookson combine their activities in a single joint venture. Chemson is born and starts operating from sites in Germany, England and Australia. |
| 1976 | Brazilian chemicals company Inbra begins manufacturing lead salts as PVC stabilisers. The stabiliser business is absorbed by the Chemetall Group in 1998. |
| 1963 | The Bleiberger Bergwerksunion (BBU) with its seat in Arnoldstein/Austria begins producing stabilisers. |
| 1953 | The Kautschuk-Gesellschaft, part of the Metallgesellschaft Group from Frankfurt/Main, embarks on the production and sales of stabilisers for PVC processing in Langelsheim. This business segment is transferred to the newly founded subsidiary Chemetall in 1982. |
| 1942 | Cookson from Wallsend near Newcastle-upon-Tyne in England starts producing lead salts as stabilisers for flexible PVC. Shortly after, Cookson opens a production plant in Sydney/Australia. |
