Gas risk in freight container handling

Background: Transport container traffic carries millions of containers worldwide. To protect transported freight and inhibit the spread of foreign species, the containers are fumigated with chemicals, some of which having effect to central nervous system. Gas components and concentrations should be known to define safe handling procedures for each container. The Finnish Work Environment Fund and VTT funded and performed project to collect the needed information, including ventilation times, to support future work to prepare instructions.
Methods: Research contained literature studies and practical measurements for ventilation times.
Results: Based on the literature study, close 80 different volatile compounds were detected, including about 60 chemical substances classified due to their occupational health risk. About 15 of those were known fumigants, others were supposed to be evaporated from the freight. Methods typically used for the measurement of gas concentrations are indication tubes, small hand held detectors and gas analysers. Their reliability and investment cost varies a lot. Ventilation times of containers loaded using separate numbers of corrugated board boxes were tested in field conditions with different loading ratios, temperatures and with different external ventilation systems. Fully loaded containers had even 60 times longer ventilation time than containers loaded partially. Thus, the ventilation of containers can take even several days, depending on the temperature and ventilation procedures.
Conclusions: To prevent occupational risks during container handling, the concentrations of harmful substances in container must be known. Today, such measurements need several analysis methods. Safe handling procedures should be based on reliable data to conclude when the safe working environment with sufficient high security margin is achieved in the container.