Recommendations. The proxy data derived from one specific chemical site has been used frequently for compiling LCI data for chemicals in the ecoinvent database, with the intention of supplementing available data and to avoid neglecting electricity, heat, water, nitrogen or infrastructure demands of chemicals production in case of data gaps. However, this study finds strong evidence that the overall proxy electricity demand used in the ecoinvent is too high, while the heat demand is far too low. In tendency, this leads to an underestimation of key environmental impacts of chemical production such as climate change. Due to the high prevalence of using the proxy data (more than 20 % of datasets in case of energy inputs), such errors can accumulate along chemicals supply chains. The cause for the differences compared to sector averages is likely due to the underlying raw data for deriving proxies for energy inputs that comes largely from a single chemical site in Germany with an unrepresentative process and product portfolio. This is concerning as the ecoinvent database has been and are expected to be widely used in the foreseeable future as the major source of sustainability assessment data for chemicals by a wide range of stakeholders. Further use of such erroneous data in the ecoinvent database will continue to perpetuate the errors and mislead decision-making. Therefore, immediate concerted efforts are warranted to correct the identified inconsistencies and errors, and make funding available for doing so.