evidence: Much of the work in the cotton fields is done by women, who frequently bring their infants and toddlers with them to play alongside the rows of cotton plants. Soviet managers of the collective farms would in some cases use aerial spraying to treat the fields with herbicides or pesticides, and occasionally would spray the crops while the workers were in the field, directly exposing them to both the aerosol of the chemicals and contaminating any exposed skin. As was the case with fertilizers, overuse of toxic chemicals was common, and substances banned in much of the remainder of the world were sometimes widely, if surreptitiously, employed in Soviet agriculture. For example, the Soviet government officially banned the production of DDT in 1970, but some sources allege the insecticide was used in Central Asia well into the 1980s. Moreover, the Soviets had an extensive biological weapons testing facility located on Vozrozhdeniya Island in the Aral Sea for several decades. In 1971, a weaponized variant of smallpox escaped the island, killing three people and forcing a massive decontamination campaign in Aralsk, the main port on the Kazakhstan shore. In recent years, the United States and Uzbekistan have jointly decontaminated several locations for anthrax, and further cleanup is planned. Vozrozhdeniya Island is no longer an island, linking with the mainland in the early 2000s as water levels dropped.