For their study, Hinz and his colleagues enlisted the help of the New Zealand customs authorities. Staff used probes, which they pushed through the rubber seals of container doors, to take gas samples from 490 sealed containers. Hinz also collected air samples from dozens of other containers herself, tracking how compound concentrations changed in real time as the containers were opened and the air inside mixed with the atmosphere. outside fresh air.
The investigation revealed many harmful substances. Customs personnel found methyl bromide, the compound that overwhelmed Rotterdam dockworkers, in 3.5% of sealed containers. They found formaldehyde in 81% of the containers and ethylene oxide in 4.7%, to name just a few of the chemicals. Exposure to ethylene oxide can cause a variety of unpleasant symptoms, including nausea, vomiting, and diarrhea. Formaldehyde, a preservative, is carcinogenic and can also cause internal irritation when inhaled, among other symptoms.
In their study, Hinz and his colleagues found that some of the concentrations measured seemed high enough to cause an acute reaction triggering immediate symptoms. However, Hinz says that, in practice, it’s unusual for a worker to come into direct contact with toxic gases at such high levels. Instead, there is a more common but still notable risk from repeated exposure to low concentrations. Chronic contact with these chemicals can potentially increase the risk of cancer or cause psychiatric problems, for example. And yet, there is relatively little research on the risks of chemicals inside freight containers.
“I really think he needs attention, way more attention than he gets,” Hinz says.
Gunnar Johanson, a toxicologist at the Karolinska Institute in Sweden, who acted as a peer reviewer for Hinz’s study, agrees with his assessment.
“We don’t know exactly how big the risk is, but it’s an unnecessary risk because you can easily deal with it,” he says. All it takes is better ventilation.
A few years ago, Johanson and his colleagues were called in to examine a suspicious container in Sweden. It was loaded with rice, but inside the container was also a strange blue bag full of white powder. When Johanson analyzed the air, he found phosphine, a fumigant, at a concentration high enough to be lethal.
To protect dockworkers, Johanson and his colleagues designed a device that connects to an exhaust fan and attaches to existing, but tiny, ventilation holes in the sides of most containers. Experiments suggest that once the device is turned on, the concentration of harmful gases decreases within minutes.
“We can reduce about 90% of volatile contaminants in an hour,” says Johanson. The device is currently used by Swedish customs authorities, he adds.
The shipping and logistics sectors should be made more aware of the dangers associated with exposure to harmful gases in shipping containers, says Martin Cobbald, managing director of Dealey Environmental, an environmental services company in the UK.
His company is frequently contracted to open and vent containers, but, he adds, “we don’t do it as much and for the range of people that we should.”