What Was the Beirut Explosion’s Health and Environmental Impact?

On August 4, 2020, a massive explosion at the Port of Beirut devastated large parts of the city, killing over 200 people, injuring thousands, and displacing hundreds of thousands. The blast, one of the most powerful non-nuclear explosions in history, was linked to improperly stored ammonium nitrate.

Beyond the immediate destruction, the disaster had lasting health and environmental consequences.

Stored Chemicals And Their Properties

The explosion was traced to approximately 2,750 metric tons of ammonium nitrate, a chemical used in agriculture as a high-nitrogen fertilizer and in mining as an explosive component. Under normal conditions, ammonium nitrate is stable, but improper storage can lead to dangerous decomposition. When exposed to heat, contaminants, or confinement, it can detonate, releasing immense energy. Its oxidizing properties intensify combustion, making it hazardous when stored near flammable materials.

At the Port of Beirut, poor storage conditions heightened these risks. Reports indicated the chemical had been kept in a poorly ventilated warehouse for nearly six years, alongside other reactive substances. Over time, moisture absorption can cause caking, increasing the likelihood of localized hotspots and self-sustaining decomposition. The presence of combustible materials, such as fireworks and fuel, may have contributed to the explosion’s initiation. Similar industrial accidents, such as the 2015 Tianjin explosion in China, have shown that ammonium nitrate becomes more volatile in humid environments where it can form an unstable slurry.

The detonation produced a high-temperature shockwave, releasing gases like nitrogen oxides (NOx) and ammonia. Nitrogen dioxide (NO₂), a reddish-brown gas, is particularly concerning due to its respiratory effects and role in environmental pollution. In urban areas, high NO₂ concentrations contribute to secondary chemical reactions, forming ozone and particulate matter that linger in the atmosphere. The explosion also dispersed fine particulate debris, including heavy metal residues from surrounding infrastructure.

Human Health Consequences

The explosion caused both immediate and long-term health effects. The shockwave, traveling at supersonic speeds, led to blunt force injuries, penetrating wounds from shattered glass, and crush-related trauma from collapsing structures. A study in The Lancet reported that hospitals admitted thousands of patients with lacerations, fractures, and traumatic brain injuries. Many required emergency surgeries, with some experiencing long-term disabilities from nerve damage, amputations, or internal injuries.

Beyond physical trauma, toxic gases and fine particulate matter posed severe respiratory risks. The detonation released high concentrations of nitrogen dioxide and combustion byproducts, exacerbating asthma, chronic obstructive pulmonary disease (COPD), and other pulmonary conditions. A post-disaster air quality assessment by the American University of Beirut found elevated levels of PM2.5—fine inhalable particles that penetrate deep into the lungs and enter the bloodstream. Exposure to these pollutants has been linked to cardiovascular disease, stroke, and respiratory infections, particularly among vulnerable populations such as children, the elderly, and those with preexisting conditions.

The psychological impact was equally profound. Studies on PTSD following large-scale explosions, such as the Oklahoma City bombing and the 2015 Tianjin explosion, indicate that survivors often face long-term mental health challenges, including anxiety, depression, and sleep disturbances. A survey by the Lebanese American University six months after the explosion found that over 70% of respondents exhibited PTSD symptoms, with many reporting persistent nightmares and heightened anxiety triggered by loud noises. The displacement of hundreds of thousands worsened mental health struggles, as people faced economic uncertainty, homelessness, and the loss of loved ones.

Environmental Toxic Residues

The explosion released hazardous substances into the environment, affecting air, soil, and water quality. The intense heat and pressure vaporized various materials, generating airborne pollutants that settled over urban and coastal areas. Nitrogen oxides and volatile organic compounds (VOCs) contributed to secondary pollutants such as ozone and fine particulate matter, reducing air quality and causing persistent smog in the weeks that followed.

Heavy metal contamination was another major concern. The blast pulverized buildings, vehicles, and industrial infrastructure, dispersing lead, mercury, and cadmium into the environment. Soil samples from affected districts showed elevated concentrations of these toxic elements, particularly near the explosion site. Lead, commonly found in older construction materials and paints, is especially hazardous due to its neurotoxic effects, particularly in children. Cadmium, present in batteries and electronic waste, accumulates in the food chain and poses risks to kidney function and bone health. Remediation efforts are challenging, requiring soil excavation or chemical stabilization to prevent further leaching into groundwater.

The blast’s proximity to the Mediterranean Sea raised concerns about marine contamination. The explosion deposited debris and chemical residues into the harbor, with satellite imagery showing suspended particles spreading into coastal waters. Hydrocarbon pollution from damaged fuel storage tanks and industrial facilities introduced benzene, toluene, and polycyclic aromatic hydrocarbons (PAHs) into the marine ecosystem. These compounds are carcinogenic and bioaccumulate in marine organisms, posing risks to both aquatic life and human seafood consumption. Local fisheries reported abnormalities in fish populations, including signs of oxidative stress and tissue damage, indicative of prolonged chemical exposure.