Introduction to Toxic Industrial Chemicals and Fumigants
One consequence of growing international trade and industrialization is the increasing trade and shipment of toxic industrial chemicals (TICs). With standards for and attitudes to these chemicals varying greatly between jurisdictions, frontline workers in the shipping and border security industries face exposure to very real, often undocumented, dangers.
Unfortunately, given the size and diversity of international trade, it has not proved possible to accurately track which fumigants and TICs are being used and shipped, what concentrations are being used and shipped, or what qualifications and experience those doing the fumigation or packaging have. A recently published study1 involving analysis of over 2000 containers arriving in the Port of Hamburg over a 10-week period clearly illustrates this problem.
Chronic reference exposure levels were exceeded in 70% of containers. Still more alarming was that 36% of the containers had concentrations over acute reference exposure levels. This means safeguards are needed to protect the health of workers involved with loading, transport, inspection, and unloading of imported goods, particularly shipping containers.
In this article, we overview the common fumigants and volatile toxic industrial chemicals TICs and compare commercially available detection technologies, including Selected Ion Flow Tube Mass Spectrometry (SIFT-MS).
A variety of fumigants are commonly used against biosecurity threats, some of which are listed in Table 1. The chemical and toxicities properties of these fumigants are very diverse.
Table 1 also lists time-weighted average (TWA) exposures given by the Australian Government’s. Note that acceptable exposure levels may differ from country to country. For example, in the United States exposure limits may be found in the National Institute for Occupational Safety and Health Pocket Guide to Chemical Hazards.
When protecting workers from these toxic chemicals it is recommended that several fumigants be detected at much lower levels than those indicated (for example, ethylene dibromide and methyl bromide, which are known carcinogens, and ethylene oxide and formaldehyde, which are suspected carcinogens).
|Fumigant name (synonyms) [CAS number1]||Examples of fumigant use||TWA2|
|Chloropicrin (trichloronitromethane) [76-06-2]||Soil; timber and timber products||0.1 ppm [0.67 mg/m3]|
|Ethylene dibromide (1,2-dibromoethane) [106-93-4]||Soil; post-harvest for crops; citrus and tropical fruits; vegetables; beehives||0.5 ppm [3.9 mg/m3]|
|Ethylene oxide (oxirane, 1-2-epoxyethane) [75-21-8]||Grains; dried fruits and nuts||1 ppm [1.8 mg/m3]|
|Formaldehyde (methanal) [50-00-0]||Eggs (killing viruses and bacterial); most commonly present due to outgassing from manufactured goods||1 ppm [1.2 mg/m3]|
|Hydrogen cyanide [74-90-8]||Fresh produce; structures; aircraft||10 ppm [11 mg/m3]|
|Methyl bromide (bromomethane) [74-83-9]||Very widely used general fumigant, but especially for wood3||5 ppm [19 mg/m3]|
|Phosphine [7803-51-2]||Grains; tobacco; dried fish and meats; fresh fruits; beverages||0.3 ppm [0.42 mg/m3]|
|Sulfuryl fluoride (VikaneTM) [2699-79-8]||Structures; timber and timber products; shipping containers||5 ppm [21 mg/m3]|
Common Toxic Industrial Chemicals (TICs)
A vast range of compounds are produced in very large quantities by industry as end products or as building blocks to form other chemicals. Among these are many toxic industrial chemicals, some of which are volatile and pose health risks to workers who are exposed to their vapors when they are transported. Table 2 lists some very common examples of volatile TICs.
|Toxic Industrial Chemical TIC Name [CAS number1]||Examples of toxic industrial chemical use||TWA2|
|Precursor for many industrial compounds||1 ppm [3.2 mg/m3]|
|Toluene [108-88-3]||Solvent, synthetic precursor, fuel||50 ppm [191 mg/m3]|
|Ethylbenzene [100-41-4]||Intermediate in synthesis of styrene||100 ppm [434 mg/m3]|
|Xylene [1339-30-7; 95-47-6; 106-42-3; 108-38-3]||Solvent, cleaner, synthetic precursor||80 ppm [350 mg/m3]|
|Styrene [100-42-5]||Synthesis of polystyrene, etc.||50 ppm [213 mg/m3]|
|Mesitylene (1,3,5-trimethylbenzene) [98-82-8]||Solvent||25 ppm [125 mg/m3]|
|1,3-Butadiene [106-99-0]||Manufacture of synthetic rubber||10 ppm [22 mg/m3]|
|Ammonia [7664-41-7]||Fertilizers, synthesis, refrigeration||25 ppm [17 mg/m3]|
|Phenol [108-95-2]||Synthesis of plastics, pharmaceuticals, etc.||1 ppm [4 mg/m3]|
|Acetaldehyde (ethanal) [75-07-0]||Synthetic precursor||20 ppm [36 mg/m3]|
|Dichloromethane (methylene chloride) [75-09-2]||Solvent, cleaner||50 ppm [174 mg/mv]|
|Chloroform (trichloromethane) [67-66-3]||Solvent, cleaner, anesthetic||2 ppm [10 mg/m3]|
|1,1-Dichloroethane (vinylidene chloride) [75-35-4]||Synthetic precursor||5 ppm [20 mg/m3]|
|Vinyl chloride (chloroethylene) [75-01-4]||Manufacture of PVC||5 ppm [13 mg/m3]|
Toxic Chemicals and Fumigants Detection Technologies
There are a number of commercially available technologies for fumigant detection, several of which are compared in Table 3. They range from the simplicity of compound-specific colorimetric tubes to the complexity of gas chromatography.
Table 3 indicates that SIFT-MS offers the most comprehensive fumigant detection solution, especially in situations where it is not known which fumigants have been used. Moreover, the high sensitivity of SIFT-MS provides added confidence that carcinogenic fumigants will be detected at levels much lower than formal TWAs, thus avoiding unnecessary exposure.
|Characteristic||Colorimetric Tubes1||Electronic Detectors2||GC Detection3||SIFT-MS|
|Breadth of analysis||One tube per fumigant tested||Limited to a few fumigants per detector||All fumigants, but this requires several analyses using different columns||All fumigants. Easily configured for detection of any additional volatile organic compounds|
|Specificity||Moderate||Low to moderate||High||High|
|Speed||Approx. 1 minute||Approx. 1 minute||> 15 minutes||< 1 minute4|
|Required user skill level||Low||Low||High||Low|
|Consumable costs per sample||High||Low||Moderate||Low|
|Maintenance||Low||Low to moderate||High||Moderate|
A diverse range of fumigants and TICs with a diverse range of chemical properties occur at harmful levels with concerningly high frequency. Until now there has not been a technology that can rapidly, accurately and simultaneously detect this range of threats. SIFT-MS, however, provides rapid and accurate broad-spectrum fumigant and TIC screening, combined with simplicity of operation.
For the first time, SIFT-MS provides workers and businesses in the shipping, freight and border security industries with a reliable and safe fumigant and TIC detection system.
- X. Baur, B. Poschadel and L.T. Budnik (2010). “High frequency of fumigants and other toxic gases in imported freight containers—an underestimated occupational and community health risk”, Occup. Environ. Med., 67, 207-212.
- C.G. Freeman, M.J. McEwan (2002). “Rapid analysis of trace gases in complex mixtures using SIFT-MS”, Australian Journal of Chemistry, 55, 491-494.
- D. Smith, P. Spanel (2005). “Selected ion flow tube mass spectrometry for on-line trace gas analysis”, Mass Spectrometry Reviews, 24, 661-700.
- B.P. Prince, D.B. Milligan, M.J. McEwan (2010). “Application of selected ion flow tube mass spectrometry to real-time atmospheric monitoring”, Rapid Commun. Mass Spectrom., 2010, 24, 1763-1769.