Two years after the so-called tainted Chinese toys and pet food scare, another Chinese manufactured product is causing safety concerns in the United States.

The U.S. Consumer Product Safety Commission (CPSC) said last week that it had received about 1,900 complaints from U.S. homeowners who claimed that Chinese drywall had made them sick or damaged their houses.

But CPSC officials conceded last Thursday that it was still too early to say whether Chinese drywall was causing health problems as well as corroded pipes, electrical outlets and foul odors in homes.

In a report last May, the U.S. Environmental Protection Agency (EPA) did not draw any conclusions about health risks or whether the boards could be damaging wiring in homes.

NO SOLID EVIDENCE OF CONTAMINATED CHINESE DRYWALL YET

According to the CPSC, consumers largely reported that their homes were built in 2006 to 2007, when an unprecedented increase in new construction occurred in part due to the hurricanes of 2004 and 2005.

Some consumers have reported a "rotten egg" smell within their homes, while others complained of irritated eyes and skin, difficulty breathing, a persistent cough, runny noses, nosebleed, recurrent headaches, sinus infection and asthma attacks, said the U.S. watchdog of consumer goods.

Moreover, consumers have reported blackened and corroded metal components in their homes and the frequent replacement of components in air conditioning units.

As many as 100,000 homes may be affected by Chinese drywall, and consulting firm Towers Perrin estimates the damage could range from 15 billion to 25 billion U.S. dollars, according to U.S. media.

Though many complaints were targeted against Chinese drywall, there is no solid evidence indicating the Chinese material caused these problems.

Tests conducted by the U.S. Environmental Protection Agency (EPA) this May found small amounts of sulfur and two organic compounds in samples of Chinese-made drywall, but the EPA acknowledged that these two organic compounds also existed in the U.S.-made drywall samples.

The EPA report did not draw any conclusions about health risks or whether the boards could be damaging wiring in homes. This suggested the Chinese drywall was not unsafe, according to some analysts.

On the other hand, the tests conducted by the CPSC, which were released last month, showed that the imported drywall had more sulfur and strontium, and emitted higher rates of volatile sulfuric compounds than comparable North American wallboard.

But CPSC officials conceded last Thursday that it was still too early to say whether Chinese drywall was causing health problems.

Some Americans also expressed concerns over making presumptions before there was solid evidence.

"I am a little disappointed in the lack of proof that Chinese drywall is what is causing the problems," said an American named Jon who left a comment on the website of the New York Times. "There don't seem to be any tests or studies in which compounds or chemicals out of the ordinary have been found.

"I want to see an actual scientific conclusion instead of knee-jerk assumption," he asserted.

Some Chinese observers also said it was unfair to blame Chinese drywall because the product was made according to standards provided by U.S. importers.

"It is unfair that now everyone says it is Chinese drywall's fault," said a Chinese expert who preferred to stay anonymous.

CHINA, U.S. TO WORK TOGETHER TO PROBE CAUSE

Quality problems may originate anywhere from raw material collecting, product manufacturing, transportation or distribution.

According to some analysts, with increasing globalization, quality problems were becoming more and more of a challenge that the international community had to cope with together.

The Chinese government has paid much attention to the drywall issue, and Chinese officials have traveled to the United States to learn more about the drywall problems.

CPSC Chairman Inez Tenenbaum, who visited China recently, noted her Chinese counterparts had provided technical help and were working with the United States to determine the cause of the problem.

"We are greatly appreciative," Tenenbaum said last week after six days of talks with officials from China's product safety watchdog, the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ).

The two agencies have pledged to pursue "cooperative scientific and fact-based investigations" into the drywall issue.

"It is CPSC's and AQSIQ's intention to determine the cause of the reported problems, with the goal of ensuring that the problems do not recur," said a joint statement issued by the two consumer goods watchdogs.

Wei Chuanzhong, deputy director of China's AQSIQ, also promised China would do more to improve manufacturers' awareness of product safety and quality requirements.