Hanoi market managers on Thursday said the liquid found in cheap Chinese bras advertised as breast-enlarging tools contains a kind of oil that can cause cancer.
But health authorities said they might not know what to do as Vietnam has few regulations about such pollutants.
Inspectors nationwide have been going after the bras since later October after several women complained that the products advertised as having special massage technology that can enlarge breasts -- made them itchy and irritated their skin to the point of rash.
The bras cost between VND55,000-90,000 (US$2.64-4.32) but some in Ho Chi Minh City cost VND500,000.
They contain small plastic bags of an oily solution advertised as silicone, which has plastic balls supposedly produce a "massage effect" that boosts breast size without plastic surgery, according to labeling found on the products.
Tests from Hanoi found the balls were made from polystyrene composite and do not have any adverse health effects.
But the liquid solution contains mineral seal oil, which can contain pollutants, especially polycyclic aromatic hydrocarbons such as the carcinogenic anthracene, benzopyrene, chrysene, coronene, tetracene, phenantherene, pyrene, pentacene, priphenylene, and ovalene.
Vuong Tri Dung, deputy head of the Hanoi Market Management Department, said the agency took 10 samples and had them tested at the Institute of Crime Science at the Ministry of Public Security.
The Vietnam Institute of Chemistry and health authorities in the central city of Da Nang also found the same results after testing the bras.
Dr Vu Duc Loi from the institute said tests have found many of the 16 polycylic aromantic hydrocarbons present in the bras.
Da Nang Health Department said it will send a report to the Health Ministry to have it decide how toxic the bras could be.
But Dang Van Chinh, chief inspector from the ministry, told Thanh Nien the ministry has no expertise in the area and it will have to consult specialists in the field.
Dr Dang Cam Ha from the Vietnam Institute of Biotechnology, said the hydrocarbons can be found in many children's toys, but a large amount of them can cause cancer, typically skin cancer.
Ha and other scientists said they would suggest authorities strictly follow international rules as Vietnam has yet to issue a safety threshold for the chemicals.
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