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Wuxi Matsushita Battery Contaminated Hundreds of Chinese Workers with Cadmium

May Wong

In early January 2007, workers from the Wuxi Matsushita Battery Co., Ltd (WMB) staged strikes to protest against the company for being responsible for their cadmium poisoning.

It was one of the cadmium incidents which spread quickly within the battery industry in China. Cadmium oxide, which is red in colour, is chiefly used in the manufacturing of nickel cadmium batteries, whose chief application is the making of negative electrodes to transmit electric current.

China as Top Battery Producer

In 2004 China produced half of the world’s batteries, 80 percent of which were for export.[1] This was the result of relocation of the industry --- along with many other industries --- to China from all over the world. In that year China exported 800 million nickel cadmium batteries, a rise of 67 percent over the 1999 level. China has thus also become the top cadmium consumption country as well: in 2004 China consumed half of the world’s cadmium production, 70 – 80 percent of which was destined for nickel cadmium batteries.[2]

Cadmium, (Cd), is a silvery white colored heavy metal. When inhaled, cadmium is eliminated from the human body via urine. However, the amount of cadmium excreted daily in this manner is very small. It represents only about 0.005 – 0.01% of the total body burden which corresponds to a biological half-life for cadmium of about 20-40 years.[3] Consequently cadmium causes long-term damage to many organs and tissues, especially the kidneys and skeletal structure. The International Agency for Research on Cancer (IARC) classifies cadmium and its compounds as îcarcinogenic to humansî (Group 1).[4] In Japan cadmium related disease, that became a big social issue during 1950s, was caused by the industrial waste water from the Kamioka Mines controlled by the Mitsui Mining and Smelting Co., Ltd. called "itai-itai disease". The severe bone pains induced by cadmium poisoning caused such distress that victims would cry out "Itai! Itai!" (means, Ouch! Ouch!)

The first outbreak of cadmium poisoning and workers’ struggle to defend their legitimate rights was the GP case in 2004. Three factories of the Gold Peak Industrial Holding Company in Guangdong, China, contaminated at least 400 workers with excessive levels of cadmium, and since then although the numbers drop to a little more than 200, the number of officially diagnosis as cadmium poisoning keep on increasing and the recent figure is 24, up from 2 in 2004. Since then the workers have been standing up to defend their basic rights which largely denied by the company, although it was responsible for the disasters for violating the basic occupational safety laws.[5] The struggle of the GP workers was important to the WMB workers because the latter only became aware of the hazard of cadmium through learning the GP case. The heroic struggle of the GP workers eventually broke the local censorship and made their case heard in the media, prompting the CCTV (China Central Television) eventually made a favorable report. The report aroused attention from the public, including workers in Wuxi Matsushita Battery Co., Ltd.

WMB Failed to Provide Efficient Protection

Wuxi Matsushita Battery Co., Ltd (WMB) is situated at New Sci-Tech District, Wuxi City, Jiangsu province. And its parent company Panasonic is one of top 500 enterprises, which established plenty of branches in different cities like Shenyang, Wuxi, Shanghai, Zhuhai etc., engaging in manufacture of electric products. In 2002 Panasonic relocated nickel cadmium battery production to Wuxi and founded WMB. WMB had 5,300 workers. Most of products of WMB are exported back to Japan. The New Sci-Tech District also houses many Japanese factories. It was reported that since the founding of the district, local people noticed the extinction of birds in the neighborhood, and the river surrounding the district turns into black.

The factory arranged medical check on workers’ cadmium level since 2003, as was required by laws. According to news report, between 2003 and 2005, 87 workers were found with excessive cadmium levels.[6] Judging from other published news reports[7] this might be an under-estimated figure. However the management failed to disclose the results to affected workers. In 2006, upon learning the GP case some workers from WMB went for medical check on their own accord. One worker was diagnosis as kidney malfunction. It alerted more workers and they demand the management to disclose the medical test results. The management refused and it triggered off a six days long strike.

WMB failed to comply with the occupational safety laws which require employers to provide efficient protection to workers against occupational hazards. The employer only provided workers with cheap cotton masks (one yuan per piece) for every two days.[8] According to the Cadmium Handbook published by the U.S.’s Occupational Safety and Health Administration, when cadmium in air is less than ten times the permitted level, the employers need to provide "a half mask, air purifying equipped with a high-efficiency particulate air (HEPA) filter." When cadmium in air is 25 times of the permitted level, "a powered air-purifying respirator (PAPR) with a loose-fitting hood or helmet equipped with a HEPA filter." The Wuxi Centre for Disease Control and Prevention admitted that the factory was found with excessive cadmium level in the air but refused to reveal which particular level it reached.[9] Still it is reasonable to suspect that cotton mask is not effective to keep off cadmium since the powder is so fine. According to some reports, devices to collect dust and the ventilation were rarely used if not simply lay idle.[10]

As to pre-work training: "Although the company presented workers with training relating to work safety and protection when they got recruited, the contents of the training mainly focused on hazards like nitric acid and potassium hydroxide and how to prevent potential harms. Though the trainer had mentioned the hazard of cadmium, but failed to instruct them how to avoid it."[11]

Workers on Strike for the Availability of Health Check-up Results

On December 14, 2006, workers at WMB watched the CCTV program on GP case. Prior to that there were already workers feeling sick and suspected that they might have gotten poisoned, and demanded, unsuccessfully, the management to release their annual medical check results. Now the workers believed that the management must be hiding something. On 4 January 2007 they demanded the company to release the results of their health check-up. Under pressure WMB provided workers with the copies of results of urinary cadmium test. The workers noticed that in some copies the date of health check-up did not match the date of the test result (for example, one worker had health check-up on August 18th 2006, but the date of test report was August 16th 2006, two days earlier than the date of body check, which was just laughable). Moreover, the reports of urinary cadmium were written by hand, not printed, and without the official seal of Wuxi Centre for Disease Control and Prevention. It’s well known that hospitals in Wuxi had accomplished the computerization of medical instruments long before; and all of laboratory sheets are printed by computers. In some of these hand written reports, the number which reflected the levels of excessive cadmium had suspicious marks of corrections. A worker’s test result was "corrected" from 5.7 μ_mol/mol (which exceeded the official permitted level) to 4.5 (below official permitted level).[12] Zhu Xiaoyu, the director of Wuxi Center for Disease Control and Prevention, when questioned by a journalist of First Chinese Business Daily explained: "It’s a clerical error!".[13]

The workers just did not believe Mr. Zhu. They suspected that the company had fabricated the results of health check-up. They demanded the company an explanation and compensation. But the management turned down their requests. The furious workers then took action. On 4 January, the workers in the department of nickel hydro battery stopped production. The next days, other workshops workers joined the strike too.[14] In the morning of 8 January, more than 1300 workers in five workshops on the first floor went on strike. The workers, full of rage, blocked the gate of the factory for 8 hours. The striking workers kept telephoning media in Jiangsu province, but none of them dared to show up. Out of helplessness, the workers elected five workers representative and sent them to negotiate with the company, demanding a second check-up in the Provincial Hospital for Treatment and Prevention of Occupational Diseases. The company claimed that it was impossible to conduct a second check-up in the hospital because the lamp of the testing machine of the hospital was damaged; and the second check up would be conducted on site in the company by people from the Center for Disease Control and Prevention of Changzhou. Hence after, the date of a second check up was rescheduled over and over again.

On January 8th, the Wuxi municipal government set up a task force which includes officials from the sanitation bureau, labor bureau, trade union, and negotiated with five workers representatives. The meeting yielded no results.

On 9 January, nine workers had acquired the results of self-paid health check-up conducted by Jiangsu Hospital for Treatment and Prevention of Occupational Diseases in Nanjing. "There is an explicit discrepancy between the results of check-up issued in Nanjing and the ones presented by the company. In the report of self-paid check-up (of one worker), the cadmium level was 5.1μ_mol/mol, which was much higher than the 1.5μ_mol/mol level of the company-arranged test. Another worker had a level of 7μ_mol/mol (the result of his self paid test), up from a level of 2.3μ_mol/mol (test result arranged by the company)."[15] WMB(The Chinese name of WMB is 無錫松下電池有限公司and Panasonic is the brand name of the battery produced by the company insisted that the results of self-paid check-up were suspicious, claiming that only the results of collective check-up arranged by the company were valid. The management’s hard line position further intensified the contradiction between the employer and the workers.

The angry workers decided to take bolder action. On the same day (9 January) they put on their factory uniform and marched more than ten kilometers in cold wind toward the municipality building, appealing to the local government to intervene on their favor. The authorities prepared for the worst. Around 11:30 a.m. when the marchers arrived at the Tangnan Xincun, the factory’s buses caught up with the workers, asking workers to return to the factory for lunch. The furious workers simply ignore them.

The local government then dispatched policemen in arms to intercept the marching workers. At 1:30 p.m., with an empty promise that "[the authorities] will handle it as soon as possible", the local officials ordered the workers gathering in front of the municipal building to get on the factory’s buses and headed back to the factory. Soon the policemen began to beat up those who were reluctant to follow orders. It’s said that a worker was hospitalized after being seriously wounded. Three women workers got arrested because they refused to on board the buses. In face of the situation, many workers wept. The workers in grief were sent back to the factory. Then the personnel department of the company bailed the three women workers out.

In a word, the municipal government and its department --- the labor bureau, the environment protection bureau and Health and Epidemic Prevention Station --- not only failed to defend the victims, but also colluded with the Company in repressing workers’ struggles. During the strike, local officials even sent police cars to the company, terrorizing workers with armed policemen.

The local media turned a deaf ear to workers’ plight as well. The operators of local television station would hang up the telephone calls without hesitation when they found out that the callers were workers of the WMB.

On 10 January the company promised to arrange a collective health check-up for all of workers on the 18th. The workers resumed work. (Workers who worked middle shift had already resumed work on 9th.) Then 11 workers collectively resigned. It was reported that the Company and local judicial department warned the workers not to reveal any evidence to outsiders.

Three hundred workers remain dissatisfied, and on 10th they attempted to march to the municipality building once again, holding slogans and banners. The response of the local government was to send more than 100 police cars guarding at the gate of WMB to stop the workers. Meantime the factory was in full alert, with entire production lines stopped. All employees except for office clerks were ordered to leave. The party secretary of Wuxi Municipal Committee, Yang Weize, appeared on the spot, accompanied by more than 200 policemen in arms to block the gate of the company. Nobody was allowed entry. Workers’ action was broken.

The public relation department of Panasonic Corporation of China issued a statement denounced some of the news reports as "seriously flawed" and warned to take legal action against those responsible. However, a report issued by 21st Century Business Herald[16] slapped in the face of Panasonic Corporation of China. The reporter had interviewed Pan Wei, the fired vice-president of personnel department of Panasonic (China); Pan admitted that the Company manipulated the results of medical check-up.

At one point the Japanese members of the Asia Pacific Workers Solidarity Link (APWSL) staged a solidarity action in front of the Panasonic headquarter in Tokyo.

Under the combined repression from both the municipal government and the Company, many workers were forced to resign. Those still working had to choose silence to protect themselves. The incident was over, at least for the moment. Yet the cadmium in their bodies was far from over. It would remain there for decades and continue to damage their organs, as are the cases of many battery workers across the country.

24 July 2008

further reading:Wuxi New District



  1. Zhongguo dianchi gongye jingying quanshu (Manuel for China’s Battery Industry), Aviation Industry Press, Beijing, 2006, p. 284.
  2. For more on the industry please refer to Chapter 10.
  3. Scientific Report on the Conditions of Work, Cadmium Exposure and Health Problems experienced by Gold Peak’s Chinese Workers, April 2007.
  4. See website of the Agency: For more information on cadmium, please refer to the document on cadmium released by the Occupational
  5. The Safe Production Law--Article 21, 36, 37, 44 and 45 state that the factory should provide safe production knowledge, training and safe operation rules for workers, notification of duties, and labor protection. The Law on Prevention and Control of Occupational Diseases—Article 13, 35 and 48 state measures employers should take regarding prevention, protection for women and young age workers, and diagnosis of occupational disease at workplace. For details, please see pp 34-38 of the report:
  6. Nanfang Daily,, 29 May 2007.
  8. “The Event Happened on January 4th Had Shocked Thousands of Chinese”, see from:
  9. “The Follow-up to the Cadmium Poisoning of Workers in WMB: the Company Claimed that the Report Is Inconsistent with the Fact”. See Xin Ming Evening News on January 16th, 2007.
  10. “The Hearsay of Cadmium Poisoning Caused Shutdown, Has WMB covered up the Fact of Exceeding Standard of Cadmium?”. See First Chinese Business Daily,by Mu Zhi and Wang Ruchen on January 17th, 2007.
  11. Ibid.
  12. The Diagnostic Criteria for Occupational Cadmium Poisoning (GBZ17-2002) requires that when two successive cadmium urine tests reveal levels of cadmium of 5 μmol/mol creatinine adjusted and above, the subject must be placed under observation.
  13. 17 January 2007. See,549114.html
  14. “The Cadmium Poisoning Incident in WMB: A Dispute upon Reports of Health Check-up”, see 21st century Business Herald, by Zhou Yang, on January 16th 2007.
  15. “The Cadmium Poisoning Incident in WMB: A Dispute upon Reports of Health Check-up”, see 21st century Business Herald, by Zhou Yang, on January 16th 2007.
  16. One of the subsidiaries of Nanfang Daily, more details at

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