Tag Archives: conventional weapons

A Terrorist’s Stockroom?: The Effectiveness of e-Marketplace Prohibited Item Policies

Christina Krawec, Research Associate (christina.1.krawec@kcl.ac.uk)


In attempts to regulate the trade of hazardous materials used in explosives or weaponry, internet marketplaces such as eBay, Amazon, and Alibaba have all implemented seller policies on their sites. Alibaba, for example, has a list of 410 radioactive, poisonous, toxic, flammable, explosive, and ozone-depleting substances that are prohibited from being listed.[1] Some work has been done to illustrate that, despite these regulations, sellers are able to sell hazardous materials. For example, Raymond A. Zilinskas and Philippe Mauger established in a 2015 study that biotechnology of concern could be acquired by non-state individuals via Alibaba.[2] Similarly, eBay has a list of 16 “explosives precursors” that are also restricted.[3] Despite eBay’s efforts to prohibit these substances, listings for some can still be found. This study shows that eBay’s listing policies are not effective in deterring users from selling what the site considers to be hazardous material.


Table 1 shows the availability of eBay’s restricted explosives materials across eBay, Amazon, and Alibaba. A listing was included in this table if the advertised substance was over 95% pure (if the purity was listed and with the exception of hydrogen peroxide), and was included regardless of quantity, physical state (e.g. liquid or solid), or marketed use. Therefore, laboratory-grade and food-grade substances in small quantities were included. This was done because eBay’s policy does not provide detail regarding the nature of the prohibited substances; it simply lists the names of the restricted compounds. Furthermore, this study assumed that the listings were truthful about the product being sold, which may not have been the case. Listings were also only included in this table if their advertised material was in stock and available for any user to purchase.

Table 1: Listings of restricted explosives precursor materials as of 4 January 2017

Explosives precursor restricted by eBay Listings on eBay Listings on Amazon Listings on Alibaba
Aluminium/aluminum powder 4 10+ 1000+
Ammonium nitrate* 0 10+ 5+
Calcium ammonium nitrate 0 0 100+
Calcium nitrate 0 10+ 100+
Hydrogen peroxide above 12% weight by weight 0 10+ 100+
Magnesium nitrate hexahydrate 3 2 100+
Magnesium powder 0 0 100+
Nitric acid** 0 0 100+
Nitromethane 0 0 50+
Potassium chlorate 10+ 0 2000+
Potassium nitrate (saltpetre) 10+ 10+ 1500+
Potassium perchlorate 0 0 500+
Sodium chlorate 3 0 1000+
Sodium nitrate 4 8 2000+
Sodium perchlorate 0 0 300+
Sulphuric/sulfuric acid 6 10+ 700+

*Material also prohibited by Alibaba                                                        **Material also prohibited by Amazon                                                                 Note that there were hundreds, if not thousands, of results for some of these chemicals. The + indicates that at least that number of listings was found, but there were so many results that there may have been more.


For the purposes of this study, searching for the prohibited materials on Amazon and Alibaba serves as a comparison of availability. Amazon, in its listing policies, has a section on explosives, but does not discuss precursors. The page does, interestingly, list nitric acid as a prohibited hazardous material, but this is the only substance that has crossover with eBay’s list.[4] In addition, the only chemical in both Alibaba’s and eBay’s lists is ammonium nitrate. Otherwise, Alibaba has thousands of legitimate listings for explosives precursors. It is notable that these lists do not correspond with internationally-recognised control lists, including those published by the export control regimes.

For Amazon, there were more listings than were included in the table. These listings either had items that were “currently unavailable” in which there was no timeline for restocking, were temporarily sold out, or they were only available for purchase by Amazon Business accounts. For example, there were over ten listings for calcium nitrate available for any user to buy on Amazon. However, with an Amazon Business account, at least five more listings became available. If a non-state actor is able to fabricate a front company and successfully create an Amazon Business account, then this could be an effective means of opening more pathways for hazardous material acquisition.

The availability of these substances despite their restricted nature illustrates eBay’s need for further oversight and more detailed policies. While monitoring e-marketplace activity is difficult due to the size of the user base and speed of transactions, the current policy does not deter users from listing certain substances. One difficulty arises from the dual-use nature of these goods. For example, potassium nitrate (saltpetre) is used in the process of curing meat, but can also be used to make gunpowder. The question of controlling the sale of dual-use items has long been a challenge for the international export control regime. How can e-marketplaces prove that buyers are obtaining saltpetre for their cured pork and not for the development of explosives?


These observations lead to possible recommendations for the improvement of e-marketplace prohibition policies.

  1. At present, listed chemicals can be bought by anyone on eBay. If the site were to restrict certain substances from being bought by anyone without a registered business (as is the policy on Amazon), this might lower the possibility of an individual with ill intent to obtain an explosives precursor. However, implementation of this policy would require careful oversight: it could also restrict innocent users from acquiring these materials for legitimate purposes.
  2. eBay could consider adding more detail to its restricted product policy. Determining an allowed quantity and purity would make the policy clearer; adding a section describing the dual-use nature of the goods would also be informative to eBay users. Having clearer policies does not solve the issue, but more detail would at least provide education for the eBay community.
  3. Standardising naming conventions would allow e-marketplaces to more easily track prohibited chemicals being posted on the site. On Amazon, eBay, and Alibaba, chemicals can be found by their written name, their formula, or their Chemical Abstracts Service (CAS) identification number. In many cases, chemicals are only listed by their written name. There are so many variations to names that it would be easier to identify listings for specific substances if they were required to include a searchable CAS number as well. The e-marketplaces could also screen postings against lists of keyword terms. In addition to preventing listings where the item might be prohibited, such an approach could be used to identify account holders who are intent on engaging in prohibited activity. In this context, retailers could be encouraged to submit some form of “suspicious activity report” similar to those used in the financial sector.

The issue of selling weapons precursor materials online has no easy answers. However, increasing awareness of these issues and the imperfections in current policies allows further discussions to be made. The international export control regime will continue to struggle with the case of dual-use goods, and e-marketplaces should be aware of the difficulties they face as part of the ongoing challenge.

[1] “Prohibited Chemicals Reference,” Alibaba.com Rules Center, 2016.

[2] Raymond A. Zilinskas and Philippe Mauger, “E‐commerce and biological weapons nonproliferation,” EMBO, 2015.

[3] “Hazardous, restricted, or regulated materials,” eBay Rules & Policies, 2017.

[4] “Hazardous & Dangerous Items,” Amazon Seller Central, 2017.


“Hazardous & Dangerous Items.” Amazon Seller Central. 2017. Accessed January 4, 2018. https://sellercentral.amazon.com/gp/help/external/200164570.

“Hazardous, restricted, or regulated materials.” eBay Rules & Policies. 2017. Accessed January 4, 2018. http://pages.ebay.com/help/policies/hazardous-materials.html.

“Prohibited Chemicals Reference.” Alibaba.com Rules Center. 2016. Accessed January 3, 2018. http://rule.alibaba.com/rule/detail/2069.htm?spm=a271m.8038972.0.0.cobpgz.

Zilinskas, Raymond A., and Philippe Mauger. “E‐commerce and biological weapons nonproliferation.” EMBO reports 16, no. 11 (2015): 1415-1420.

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