The dioxin levels in the blood samples taken from residents of Vietnam's Bien Hoa city are 135 times higher than the levels found in the blood of residents of the capital Hanoi. This was revealed in a recent study carried out by Arnold Schecter of the University of Texas Southwestern Medical Centre, usa. The high levels can be attributed to Agent Orange, a defoliant that was sprayed by the us army in the city during the Vietnam war. The researchers said that some of the affected residents are children born many years after the war ended, indicating that they were recently exposed to a persistent source of contamination. "These are the highest levels we have seen since 1973, when the spraying of Agent Orange was stopped," said Arnold Schecter, the study's lead author. Exposure to Agent Orange has been associated with cancer, birth defects and miscarriages (see 'A generation scarred', Down To Earth, Vol 7, No 15, December 31, 1998).