Task-based transient volatile organic compounds exposure during tanker loading and unloading among hazardous chemical transport workers in South Korea.

Hazardous chemical transport workers may experience task-specific transient exposure that is not adequately characterized by conventional time-weighted average (TWA) exposure assessment during tanker loading and unloading operations. This study evaluated occupational exposure to hazardous chemicals among transport workers during actual tanker loading and unloading operations using both conventional personal sampling and real-time volatile organic compound (VOC) monitoring. Field exposure assessments were conducted during 9 loading and unloading operations at 2 workplaces. Loading and unloading activities were classified into 3 work stages: hose connection, chemical transfer, and hose disconnection. Personal exposure was assessed using both active and passive sampling methods, while transient VOC concentrations were evaluated using real-time monitoring. Personal exposure levels measured by conventional sampling were generally low or non-detectable and remained below applicable occupational exposure limits. In contrast, real-time monitoring revealed repeated transient increases in VOC concentrations during hose disconnection, with peak concentrations exceeding 2,500 ppb during phenol loading, approximately 1,200 ppb during xylene loading, and approximately 16,000 ppb during toluene loading. Although these transient peaks did not exceed the applicable short-term exposure limits, they demonstrated short-duration exposure events that were not adequately reflected by TWA measurements. These findings indicate that hose disconnection represents a critical exposure task during tanker loading and unloading operations and highlight the value of task-based exposure assessment for identifying transient exposure events. Engineering controls to reduce residual chemical release, together with appropriate personal protective equipment management, should be considered to improve occupational exposure management for hazardous chemical transport workers.