The present invention relates to polyurethanes obtainable via mixing of (a) polyisocyanate, (b) polymeric compounds having groups reactive toward isocyanates, (c) catalyst, (d) aliphatic hydrocarbon having from 2 to 15 carbon atoms and comprising at least one heteroatom selected from the group consisting of oxygen, nitrogen, and sulfur, and comprising at least one bromine and/or chlorine atom, (e) optionally blowing agent, (f) optionally chain extender and or crosslinking agent, and (g) optionally auxiliary and/or additives to give a reaction mixture and allowing the reaction mixture to complete its reaction to give the polyurethane, where the aliphatic hydrocarbon (d) comprises no phosphoric ester, polyphosphate, phosphonic ester, or phosphorous ester. The present invention further relates to a process for producing such polyurethanes, and to their use in the interior of conveyances.