'Hidden killer' hidden in containers

Many toxic chemicals that can cause immediate death, or have chronic effects, have been found inside cargo containers.

Little did they know that the shipping container was filled with toxic gas.

But just a moment after opening it, the two workers began to feel it. An unconscious man, having an epileptic seizure. The other person feels a burning sensation in his throat and starts drooling uncontrollably.

The shipping documents accompanying the container indicated it contained glassware and ceramics. The workers had no reason to suspect that they were in danger. But the worst happened. Fortunately, the ambulance team arrived in time to assist. Upon arrival at the scene, first responders saw the man having a seizure and quickly anesthetized and intubated both workers. In the ambulance on the way to the hospital, the medical staff also began to feel uncomfortable: sore throat, itchy eyes and increased salivation.

The workers will be oblivious to what awaits them in the containers.

The scary and little-known incident happened in 2006 at a port in Rotterdam, the Netherlands. Thankfully, everyone involved survived. The toxic gas that attacked them was methyl bromide, an odorless and colorless gas. Acute doses of methyl bromide can be fatal, and both chronic and acute exposure are associated with an increased risk of prostate cancer.

In the years since the day of the accident, researchers have not stopped learning about the toxic chemicals that sometimes lurk inside sealed shipping containers.

Ruth Hinz, a doctoral candidate at Massey University in New Zealand, led a recent study into the catalog of harmful chemicals in the air inside samples of containers shipped to New Zealand. Hinz's work is similar to a recent study done in Sweden, which found that about one in every eight containers arriving in the country contained dangerous levels of airborne chemicals. And when port workers open a container, they have little way of knowing what awaits them.

"It could be a cocktail with a mix of chemicals in a container," Hinz said. "You never know what's going to be in there."

Some hazardous chemicals are pumped into cargo containers for disinfection purposes. Methyl bromide is one example, although its use is now tightly regulated or banned in many countries. But an additional challenge for port workers is the presence of other dangerous gases that can be completely unexpected. As in Rotterdam, the lack of warning labels can also mask a hazard.

Containers are still the most popular means of transporting goods today.

Before sending the container out, workers at the port of departure sometimes disinfect the containers with pesticides, especially if it is a container for food, fodder or wood. These chemicals, such as methyl bromide, ethylene oxide, and phosphine, can cause a variety of symptoms in people exposed, including nausea, skin irritation, seizures, and even death.

Some goods can even produce harmful chemicals. For example, product packaging may contain toluene, while plastics may emit benzene. And these chemicals can damage bone marrow and cause anemia with prolonged exposure.

And there may be substances from the previous cargo left inside, lining the inside of the box. Workers may not realize that such hazardous substances await them in a newly arrived container.

For their study, Hinz and her colleagues used data collected by New Zealand customs. The staff used probes, which they could push through the rubber gaskets of the container doors, to collect gas samples from 490 sealed containers. Hinz also collects air samples from dozens of other containers herself, monitoring how concentrations of compounds change in real time as they are opened and the air inside is mixed with air. fresh outside.

The investigation revealed many critical problems. Customs officers found methyl bromide, the compound that stunned and unconscious workers at the port of Rotterdam, in 3.5% of the sealed containers. They found formaldehyde in 81% of the containers, and ethylene oxide in 4.7%, among other chemicals. Exposure to ethylene oxide can cause various unpleasant symptoms, including nausea, vomiting, and diarrhea. Formaldehyde, a preservative, is carcinogenic and can also cause respiratory irritation when inhaled, among other symptoms.

In their study, Hinz and her colleagues found that some of the concentrations measured appeared to be high enough to cause an acute reaction and immediate symptoms. However, Hinz said that, in practice, direct exposure of a worker to such high levels of toxic gases is quite rare and just unusual. But instead, there is a more common but still noticeable risk of repeated exposure to low concentrations. For example, long-term exposure to these chemicals can increase the risk of cancer or cause mental problems. However, there is currently little research on the risks of chemicals inside cargo containers.

'I definitely think this needs attention, even more attention than it should have,' Hinz said.

Ventilation holes on the container, however, alone are not enough to reduce toxic gases inside.

Gunnar Johanson, a toxicologist at the Karolinska Institutet, Sweden who acted as a reviewer for Hinz's study, agrees with her assessment.

'We don't know exactly how big the risk is, but it's an unnecessary risk because you can easily deal with it. All it takes is a better ventilation system," he said.

A few years ago, Johanson and his colleagues were called in to inspect a suspicious container in Sweden. It was filled with rice, but also contained a strange blue bag filled with white flour. When Johanson analyzed air samples, he found phosphine, a disinfectant, in concentrations high enough to cause death.

To protect port workers, Johanson and his colleagues designed a device that connects to the exhaust fan and attaches to the ventilation holes, which are present on the sides of most containers. Experiments show that once the device is turned on, the concentration of harmful gases drops within minutes.

'We can reduce the amount of pollutants evaporating by about 90% in an hour,' he adds, and the vehicle is currently used by Swedish customs.

Martin Cobbald, chief executive of Dealey Environmental, an environmental services company in the UK, also says there is a need for greater awareness in the transport and logistics industry about the dangers associated with exposure to harmful gases in shipping containers.

• His company regularly contracts to open and ventilate the containers, but he says: 'We're not doing it enough and for as many people as we should'.