Regulators confirmed on Tuesday some polyvinyl chloride (PVC) food wrappers used in China contain DEHA, a substance that may cause cancer.

The announcement responds to rumours circulating among manufacturers, media outlets and the public, but clearly gives rise to justifiable concerns.

Following a survey of 44 varieties of food-covering films, the General Administration of Quality Supervision, Inspection and Quarantine admitted in a press release that some PVC products are "problematic."

The administration warned the public of the potential danger and promised to conduct checks to take these products off the shelves and punish companies that continue to use them.

Quality regulators have responded promptly, which is noteworthy. The media raised the matter just weeks ago.

But the public is right to demand more from the administration, which should be pre-empting hazards instead of coming up with post-crisis remedies.

A number of food safety incidents have emerged this year, demonstrating the lack of proper standards as well as the failure of regulators to fully carry out their daily duty to ensure the quality of food.

In the current case, fingers have been pointed at national standards, which are said to lag behind international regulations.

Indeed, the national standard on PVC food-covering films, released in 1988, does not forbid the use of DEHA.

But a 2003 national standard on chemical compounds used in wrapping materials does not include DEHA on the list of safe substances, meaning its use is illegal.

Unlike in previous cases, there is an applicable standard in place, which producers have ignored and regulators have failed to act on, until prompted by the media.

There are echoes of the Fuyang fake milk powder incident of last spring, which killed 12 babies. There certainly is a standard for milk products, but the shoddy powders were being sold without being detected until the deaths aroused media attention.

Both incidents, although with different outcomes, demonstrate how slow market supervisors act, when they should be preventing health hazards.

Being a regulator is not easy. They need to study the existing rules, examine possible loopholes and urge relevant departments to improve them.

More importantly, they must carry out regular and effective market checks to ensure producers abide by relevant standards and their products do not harm the health of the people.

(China Daily October 27, 2005)