Recent news about bromide poisoning in Angola piqued my interest in the chemical sodium bromide (NaBr). This article in pravda mentions the use of NaBr in Angola’s oil industry. The USGS fact sheet on bromine (Br) lists its uses in fire retardants, agriculture, petroleum additives, well drilling fluids, sanitary preparations, and as a intermediate in chemical syntheses. Apart from its use in the photographic industry, NaBr is also used as a oil well completion fluid and workover fluid. The function of the bromide ion is probably to prepare brines/fluids to match the physico-chemical characteristics (density, pH etc.) of the reservoir fluids. The USGS fact sheet on Br mentions that while chlorine and iodine may be substituted for Br in a few chemical reactions and in petroleum additives, there are no satisfactory substitutes for Br in oil and gas well completion and packer applications.At this point, it is not clear if the source of the poisoning is inorganic (NaBr) or organic (bromocarbons). As alluded here, NaBr could be easily confused with common salt (NaCl). Approximately 60% of Angola’s current oil production comes from Cabinda (an exclave of Angola), a majority of which is offshore. Therefore, it is hard to imagine crude oil/gas production being the source of poisoning. However, bromine is also used for making organic compounds. Downstream petrochemical production could be one such consumer of bromine. A South African newspaper points to pollution caused by a petrochemical plant that has been shut down since October as a possible source. The “heavy green cloud” mentioned in the article points to the denser-than-air nature of this chemical. However, in a cursory wikipedia search for organic bromine containing compounds, I found that most of them were yellowish/colorless. Therefore, at this point, it is not very clear what cause of poisoning is.