KIEV, Sept. 13 – Horlivka-based OJSC Stirol Concern in Donetsk region has joined OstChem Holding AG (Austria), which is controlled by businessman Dmitry Firtash's Group DF, Group DF said in a statement.

According to Group DF, OstChem also incorporates nitrogen fertilizer producers JSC Nitrofert (Estonia) and CJSC Tajik Azot (Tajikistan).

Ukrainian-based nitrogen fertilizer producer OJSC Rivneazot also belongs to OstChem Holding.