BEIJING (AP) -- China's unfolding scandal involving domestically produced baby formula tainted with the industrial chemical melamine has reawakened fears over product safety amid rapid economic growth and lax regulation across the sprawling nation of 1.3 billion people.
By Thursday, health officials reported four deaths tied to the tainted formula, at least three of them infants, while the number of sickened babies had risen to 6,244. More than 1,300 babies, mostly newborns, remain hospitalized, with 158 suffering from acute kidney failure.
Thus far, all of the deaths and illnesses have been linked to formula from one producer, Sanlu, based in the northern Chinese city of Shijiazhuang.
Already, 18 people have been arrested in relation to the scandal, six of whom allegedly sold melamine, while the other 12 were suppliers accused of adding the chemical to milk.
The concerns have since spread to neighboring Hong Kong, where milk, yogurt, ice cream and other products made by Yili Industrial Group Co. have been recalled after melamine was found in eight of 30 sample products tested by regulators.
Some questions consumers may be asking:
Q. What is melamine and why was it added to raw milk?
A. Melamine is a chemical that can be derived from coal and is about 66 percent nitrogen. It is combined with other chemicals to produce plastics. It is found in fertilizer, flame retardant clothing, countertops, dyes, glues and many other household items. When added to milk, it gives the appearance of higher protein levels, even though it contains no nutrients. Most protein tests take nitrogen levels, so melamine's chemical structure is able to fool the instruments. Some dairies water down their milk, and melamine boosts protein readouts to mask the result.
Q. How does melamine harm those who ingest it?
A. Melamine is blamed for causing kidney stones leading to renal failure among infants. U.S. scientists last year hypothesized that it combined with another chemical, cyanuric acid, to cause kidney failure in cats and dogs in North America who ate pet food made from imported Chinese ingredients.
Q. When was latest outbreak detected and how did companies and officials respond?
A. The company at the heart of the scandal, Sanlu, which is 43 percent owned by New Zealand's Fonterra, received complaints as early as March and company tests in August found the milk powder contained melamine. However, no recall was ordered until Sept. 11, after New Zealand Prime Minister Helen Clark informed officials in Beijing of the problem. Some have speculated that Sanlu held off on taking action to avoid a national embarrassment during August's Beijing Olympic, although no one in the company has confirmed such talk.
Q. Were any of the milk products exported outside of China?
A. Yes. Guangdong-based Yashili and Qingdao-based Suncare, have recalled tainted milk powder that was exported to Bangladesh, Yemen, Gabon, Burundi and Myanmar. In Hong Kong, milk, yogurt, ice cream and other products made by Yili Industrial Group Co. were recalled.
Q. What are the long-term plans to deal with the problem?
A. Overseas regulators stepped up testing for melamine following last year's pet deaths. U.S. authorities meanwhile have been working with Chinese regulators to boost their own system of inspections and testing, although those stricter rules have yet to be consolidated at the grass roots. No announcements have been made concerning tighter controls over Chinese melamine production and distribution.