Transport container traffic carries millions of containers around the globe annually. Cargo containers are fumigated to inhibit the spread of foreign species, pests and micro-organisms. Transported products may also release volatile organic compounds (VOC) from the solvents, coatings and glues used in manufacturing processes.
Work safety regulation requires the employer to guarantee a safe working environment for the employees. While the regulation is not specific about how this should be achieved, in this article we want to address the question why container measurements are not only a recommendable practice but absolutely essential.
Dangerous Gases in Shipping Containers
The occurrence of dangerous gases in shipping containers is very common. Research has shown that about 10-20% of containers have concentrations of gases that exceed occupational hygiene limit values. In other words, anyone who enters a shipping container is facing a real risk of exposing to danger. As the amount of shipping containers transported around the world continues to increase, a growing number of people are becoming exposed to this problem. The risk of encountering a container with toxic gases makes this a severe problem especially due to the extreme toxicity of some of the chemicals involved. New hazardous chemicals are detected on a yearly basis.
The Finnish Work Environment Fund and VTT funded and performed a project to collect the needed information to support future work to prepare instructions for the safe handling of containers. Data was collected from seven reports, covering measurement results from 18 520 containers.
About 80 different volatile compounds were found from the data, 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.
The list of gases is long because there is an infinite number of different products shipped in containers. For instance, formaldehyde is frequently found in freight containers that carry cheap furniture. Plastic or rubber products on the other hand can give off industrial chemicals such as styrene, benzene or toluene.
There are two ways how hazardous chemicals build up in containers:
- Containers are fumigated to protect the cargo and to avoid the spreading of pests and micro-organisms. Toxic chemicals are inserted into the container and while the container should then be ventilated sometimes these chemicals still remain. The chemicals used for fumigation are often very toxic and can form a serious danger to human health even at very low concentrations.
- Off-gassing from transported products or packaging materials. The concentrations of these vapors may be significant in the confined space of the container.
The gases evolving from off-gassing are actually found more often than fumigants and make up the majority of containers with gas concentrations above exposure limit values.
Health Problems Associated with Exposure to Hazardous Gases
The specific health problems associated with exposure depend on the gases and concentrations of the gases involved. Exposure to high levels of very toxic gases, like fumigants, will lead to acute symptoms and require instantaneous treatment while exposure to others can cause issues even years after exposure.
Acute intoxication is easily attributed to gas exposure, because its effects are imminent. To attribute long-term health effects to their cause is harder. Exposure to carcinogenic substances could, for instance, cause cancer long after the event of exposure. What’s worse is that if the exposure to carcinogens was not known the cause of the disease may never be identified.
Need for Technology to Measure Multiple Gases Simultaneously
It seems clear that it’s essential to monitor for gases to prevent acute problems and to learn about long-term exposure. Container measurements present a challenge for most technologies however. It is difficult to say what gases are present in a given container so there is always a certain degree of uncertainty present. As potentially hazardous gases originate from a variety of different sources, the amount of gases that need to be monitored is very large.
As different gases are not equally dangerous and become problems at different concentrations it is also important to be able to distinguish between different compounds. This way you can avoid false alarms caused by harmless components.
Despite the challenge, employers have a duty to look after their employees’ safety and therefore have to ensure that they are not exposed to hazardous gases. And the only way to find out what gases are present is to measure them. External signs of hazardous gases in a container do not necessarily exist, so reliable procedures involving the use of technology are necessary to handle the risk.
Fortunately, there is a solution. Read more about FTIR (Fourier Transform Infrared Spectroscopy) technology that allows the reliable detection of multiple gases simultaneously.