Anacards

The anacard, a close relative to the mango found in southeast Asia, secretes an oily coat during the rainy season as a protection against bugs feeding on the immature fruit. This clear coat prevents insects from burrowing and laying their eggs in the fruit as well as eating the flesh. The coat is naturally removed during the rainy season. However, if there are insufficient rains, or if the rains arrive early, the coat will dry at the end of the season, becoming very flammable. The anacards if exposed to a constant dry heat of over 41°C can burst into flames, becoming incendiary bombs that can ignite the dry understory. During several instances in recorded history, large portions of the countryside were engulfed in flames, due to a convergence of “perfect storm” conditions. The famous Battle of Zhennan Pass (also known as the Tonkin Affair) during the Sino-French war occurred just days after a large anacard fire had ceased. More recently, during the Vietnam war, the Vietcong tactically used dried anacard mixed with cow dung as a simple napalm.

In the past decade, Vietnam has been exporting more and more mangos into the United States. The anacard, which to the American consumer eye, is indistinguishable from the mango, is often slipped into shipments of mangos. Growing anacards requires much less maintenance compared to mangoes, as anacards can grow on its own in the wild and a new tree will produce fruit after only 3 years (mango trees take at least 8 years to fully mature and produce fruit). Because these trees are easier to grow, and wild ones are prevalent in the forests, Vietnamese farmers will often slip anacards into mangos shipments to meet quotas.

In 2001, this first became a problem when a faulty refrigerator container carrying mangos on the deck of the MSC Zurich malfunctioned. As the temperature in the container increased, a few anacards burst into flames causing a fire which destroyed close to 20 containers before it was extinguished. The most severe anacard incident occurred in late 2004 in a supermarket in Eugene, Oregon where a display of mangos under bright halogen lights ignited, destroying over half the store and two neighboring buildings . Three people, including an infant, were hospitalized with minor injuries. Oregon has since banned the importation of any mangoes originating from Vietman and similar legislation is expected in several other states. The USDA is currently investigating preventative strategies to screen mango shipments originating from Vietnam for anacards before they leave port. but these screens will not be in place before the end of 2009.