Chemicals in Containers

The problem of hazardous chemicals in shipping containers has become a topic of major concern over the last 10 years. The combination of sealed containers and long journey times means that hazardous chemicals can build to a level that would never normally be encountered in domestic or industrial settings. The problem is exacerbated by the massive variety in chemicals involved, the origin of many containers in countries with less strict health and safety controls, and the often poor documentation accompanying the containers.

2013.02.19 - Chemicals in Containers

It has been estimated that about 15% of containers contain dangerous levels of chemicals, with about 0.5 percent presenting an immediate risk to health for workers at the receiving port. In the past, workers unaware of the risks have been exposed to these chemicals over long periods of time, and suffered health problems as a result, such as headaches, nausea, dizziness, and shortness of breath.

The chemicals involved are often odourless, and fall into two main categories:

  1. those used to fumigate the cargo in transit
  2. those emitted by the cargo itself

Fumigants initially received the greatest attention due to a couple of high profile cases of poisoning, but further large scale studies of containers have shown that chemicals from cargo are of equal, if not greater, concern.

Fumigants

Regulations laid out by the United Nations under ISPM15 (International Standards For Phytosanitary Measures No. 15 (ISPM 15) is an International Phytosanitary Measure developed by the International Plant Protection Convention (IPPC) that directly addresses the need to treat wood materials of a thickness greater than 6mm, used to ship products between countries) stipulate that containers carrying certain types of materials (eg. wooded packaging and dunnage) should be fumigated to control the spread of pests and diseases. Although a relatively small percentage of containers are actually fumigated, those that are can present a serious health hazard, due to the toxicity of the chemicals involved, combined with the high levels needed for effective treatment. Alternatives to fumigation such as oxygen depletion and heat treatment are available, but may be more expensive or not appropriate for the type of cargo.

Thankfully, this situation is now starting to change in some countries at least, with ports routinely monitoring suspect containers, and passing on any costs associated with decontaminating the container back to the importer. Four main fumigants are of concern, though of course other pesticides may have been applied to foods before loading into the container. Methyl bromide was for a long time the fumigant of choice due to its ease of dispersion and effectiveness. However, it is also a potent ozone depletant and greenhouse gas, and is now banned in the European Union (EU), although it remains permitted for the treatment of solid wood packaging in ISPM15-compliant countries elsewhere. Phosphine is the major alternative to methyl bromide, and is typically supplied to the container as aluminium phosphide, a solid chemical that reacts with the water in the atmosphere to produce phosphine gas. In addition to gas remaining in the container upon arrival, the aluminium phosphide can fail to react completely during the voyage, leading to the production of large amounts of phosphine upon cleaning the container. Sulfuryl fluoride was little-used in the past, but appears to be undergoing a revival following the banning of methyl bromide. Chloropicrin is a pesticide in its own right, but is usually used with methyl bromide or sulfuryl fluoride to enhance effectiveness, and as a warning agent due to its pungent smell.

Chemicals emitted by the cargo

A massive variety of chemicals are used in the production of consumer goods, and over the past couple of decades releases of residual chemicals from products ‘material emissions’ has received increasing attention from the public and governments. In many countries, legislation is now coming into force that places the onus upon manufacturers to prove that their products do not emit harmful levels of chemicals, such as the Construction Products Regulation (CPR) in the EU.

Products intended for indoor use are of particular concern, especially with the rise of energy-efficient draught-proofed buildings with lower rates of air exchange that allow levels of chemicals to build up. Similar logic applies to the air in containers, but in this case the problem is multiplied by the large number of products often fresh off the production line, and therefore emitting high levels of chemicals.

Goods where glues or solvents are used in the manufacturing process are a particular concern, for example shoes and electronics. Chemicals of particular concern include low-boiling hydrocarbons such as benzene and toluene, and chlorinated solvents such as 1,2-dichloroethane. These are generally less acutely toxic to humans than fumigants, but can nevertheless be harmful. In particular, there is very little information on the hazards posed by long-term exposure to low levels of these chemicals, or on possible additive effects from simultaneous exposure to multiple chemicals.

This post is an abstract of a technical paper written by Caroline Widdowson, Material Emissions Specialist, Markes International and initially published in the Port Technology website. A direct link to original article is given below.

Source: Port Technology

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