Continuous exposure to a high concentration of hydrocarbon fumes in a poorly managed petrochemical factory can produce significant toxic effects even before an explosion occurs. When the accumulated vapour ignites, the workers may be exposed simultaneously to intense heat, flame, smoke, incompletely combusted hydrocarbons, and other toxic products of combustion. From a CBRNE and hazardous-materials perspective, this represents a combined chemical, thermal and inhalational injury. The eyes and respiratory system are particularly vulnerable because they are directly exposed to the contaminated atmosphere. In the eyes, the first pathological event during a hydrocarbon-vapour fire is usually thermal injury to the exposed ocular surface. The eyelids may undergo painful erythema and superficial or deeper burns. Reflex closure of the eyelids provides some protection, but intense heat can still injure the conjunctiva and cornea. The conjunctival vessels become congested, producing marked redness, while conjunctival edema or chemosis may develop. Severe exposure can cause epithelial damage to the cornea, producing a corneal abrasion or epithelial defect. The patient may complain of severe pain, burning, foreign-body sensation, photophobia and excessive watering. The corneal epithelium is particularly sensitive to direct thermal and chemical irritation. Hydrocarbon fumes and combustion products may disturb the tear film and damage epithelial cells. More severe injury can involve the deeper corneal layers, causing stromal edema, haze and loss of transparency. In extensive burns, limbal epithelial stem cells may be damaged. Limbal ischemia is an important sign of severe ocular surface injury because it may interfere with normal corneal regeneration and lead to persistent epithelial defects, scarring and vascularization. In extreme cases, ulceration, thinning or perforation of the cornea can occur. The ocular injury may also involve the anterior chamber. Severe inflammation can produce cells and flare, while increased intraocular pressure may occasionally occur. Eyelid burns can cause swelling that prevents adequate examination of the globe. Foreign particles, soot or particulate matter may become embedded beneath the eyelids or in the conjunctival sac and produce additional corneal abrasion. If the worker has been exposed directly to flame, associated facial burns and periocular tissue damage should raise suspicion of more extensive ocular involvement. The lungs are at even greater risk because the worker inhales the heated and contaminated atmosphere. The pathology depends upon the concentration and composition of the fumes, duration of exposure, temperature of the inhaled gases and products generated during combustion. Chronic exposure to heavy hydrocarbon fumes before the accident