Zinc Phosphide and Aluminum Phosphide Poisoning in Iraq: A Five-year National Retrospective Analysis (2021-2025)

Abstract

Background: Ingestion of a commonly available rodenticide can result in zinc phosphide (Zn₃P₂) and Aluminum phosphide (ALP) poisoning, a potentially fatal toxicity. Phosphine gas (PH₃), which inhibits mitochondrial cytochrome C oxidase and results in multiorgan cellular hypoxia and death, is produced when zinc phosphide comes into touch with stomach acid. In extreme cases, death varies from 37 to 100%; there is no known cure. Its a dark gray or black crystalline powder, zinc phosphide is used as a rodenticide against mice, squirrels, rats, and gophers. Objectives: the goal of this study is to provide a five-year national retrospective analysis of zinc phosphide and aluminum phosphide poisoning cases in Iraq from 2021 to 2025. Method: This work created a diagnostic methodology for identifying phosphine gas (PH3) in human gastric tissue samples and cross-examined post-mortem forensic records. The traditional Silver Nitrate (AgNO3) paper test was used for qualitative screening, and stomach contents were treated with diluted sulfuric acid (H2SO4). A chemical differentiation spot test using potassium permanganate (KMnO4) and benzidine reagent was used to remove false positives from sulfur compounds (H2S), producing a clear blue hue. Advanced automated Headspace Gas Chromatography-Mass Spectrometry (HS-GC-MS) was used to obtain the qualitative and quantitative validation. Results: A retrospective analysis of five years' worth of data (2021–2025) from every governorate in Iraq excluding the Kurdistan region governorate, data collected from Medico-Legal Directorate showed a total of 250 documented deaths from phosphide poisoning, mortality increased from 48 cases in 2021 to 58 cases in 2025, with temporary decline in 2022. Discussion:  This five-year retrospective analysis showed a worrying rise in deaths from phosphide poisoning in Iraq, especially between 2023 and 2025. The results indicate that there is still a serious risk to public health from the broad availability and accessibility of zinc phosphide and aluminum phosphide. The steady increase in mortality emphasizes the need for more stringent regulations, increased public awareness, and improved preventative measures. To better understand the regional and demographic trends linked to phosphide poisoning in Iraq, more epidemiological research is advised. In conclusion:  In Iraq, phosphide poisoning continues to be a significant contributor to poisoning-related deaths. The rising trend seen throughout the course of the study emphasizes how urgently public health initiatives and regulatory actions are needed to lower exposure and stop deadly consequences.