Severe Burns from Hot Mix Asphalt
HighDirect contact with hot mix asphalt at temperatures between 130-160°C causes severe burns that penetrate deep tissue layers. Unlike water-based burns that can be quickly cooled, asphalt adheres to skin and clothing, continuing to cause thermal damage until completely removed. Workers face exposure when hand-placing material around utility covers, raking surface imperfections, shovelling material from paver hoppers, or clearing blockages from feeders and augers. Splashing can occur when material is dumped into paver hoppers or when working in wet conditions. Burns to hands, forearms, and lower legs are most common, but facial burns can occur from splashing. The viscous nature of hot asphalt makes it difficult to remove quickly, extending burn duration and severity.
Bituminous Fume Exposure
HighHot asphalt releases complex mixtures of bituminous fumes containing polycyclic aromatic hydrocarbons (PAHs), hydrogen sulfide, sulfur dioxide, carbon monoxide, and volatile organic compounds. These fumes are visible as blue-grey vapour rising from hot material and are particularly concentrated during initial placement and compaction operations. Workers operating pavers, screed operators, and labourers working in close proximity to fresh asphalt experience highest exposures. Enclosed environments such as tunnels or covered areas amplify exposure levels. Short-term effects include respiratory irritation, eye discomfort, nausea, and headaches. Long-term exposure is associated with increased cancer risks, chronic respiratory conditions, and dermatological problems. Fume composition varies with asphalt temperature, mix design, and aggregate properties.
Mobile Plant Collisions and Interaction
HighAsphalt paving operations involve coordinated movement of multiple heavy vehicles including delivery trucks reversing to paver hoppers, pavers moving forward continuously, and multiple rollers working in sequence behind the paver. Workers must position themselves between mobile plant for material placement and raking operations, creating constant risk of being struck or crushed. Reversing trucks have limited visibility of workers behind vehicles. Paver operators focus on line and level, reducing awareness of workers near the machine. Rollers operate close to paver with limited stopping distance if workers step into the pathway. Communication challenges due to noise levels and diesel exhaust obscuring visibility compound these risks. Night works amplify collision risks due to reliance on artificial lighting and reduced contrast perception.
Vehicle Impact from Live Traffic
HighAsphalt operations frequently occur on operational roads with traffic management controlling but not eliminating vehicle movements near work areas. Despite advance warning signage and speed restrictions, vehicles regularly encroach into work zones due to driver inattention, excessive speed, impairment, or distraction. Workers are exposed when setting up work zones, during paving operations, and when performing edge work and tie-ins. Night works increase risk as motorists have reduced visibility and workers' silhouettes are harder to distinguish. The linear nature of road paving means workers progress along roadways for extended periods, maintaining constant traffic exposure. Weather conditions including rain, fog, or setting sun can reduce driver visibility of work zones.
Heat Stress and Thermal Strain
MediumWorkers experience significant thermal load from multiple sources: radiant heat from hot asphalt surfaces (often exceeding 60°C surface temperature), direct solar radiation during summer months, physical exertion from manual handling and continuous standing, and insulating effect of required PPE including long pants, long-sleeved shirts, and gloves. Paver and roller operators in enclosed or partially enclosed cabins face additional risks if air conditioning is inadequate or fails. High humidity reduces evaporative cooling effectiveness, amplifying heat stress risks. Symptoms progress from heat exhaustion including fatigue, nausea, and confusion, to heat stroke which is a medical emergency. Older workers and those with cardiovascular conditions face elevated risk. Production pressures to maintain paving continuity can discourage workers from taking breaks needed for cooling and rehydration.