Foxconn Worker Protest, September 2012
Workers clean up glass shards from the broken windows near an entrance of a Foxconn Tech-Industry Park in Taiyuan, Shanxi province, Sept. 24, 2012, following a riot between workers and security guards. Reuters

Don't mess with workers' bathroom breaks. That was the lesson a Japanese electronics manufacturer learned after about 1,000 workers at its Shanghai plant were so outraged about a strict new policy limiting toilet time to two minutes that they took managers hostage for more than 24 hours.

Hundreds of police responded to the situation, which ended late Saturday with the release of the hostages, identified as 10 Japanese employees and eight Chinese plant managers, according to a statement by Shinmei Electric Co. Ltd. of Kawasaki, Japan.

"The workers demanded the scrapping of the ridiculously strict requirements stipulating that workers only have two minutes to go to the toilet, and workers will be fined 50 yuan [$8] if they are late once and fired if they are late twice," a security guard identified as Feng told the Associated Press on Tuesday. "The managers were later freed when police intervened and when they agreed to reconsider the rules."

Shinmei, a privately held company, manufactures an assortment of electronic components, mainly switches and solenoids used in other electronics manufacturing. The workers took the hostages as the company’s president, Hideaki Tamura, was touring the facility, according to the South China Morning Post. The policy changes were apparently linked to the acquisition of the facility by a Chinese firm based in Dalian, Liaoning province, and a renewal of a contract between the Chinese acquirer and its Japanese partner.

One of the protesting workers posted a message online saying they earn about $320 per month and faced fines of about $16 each time they spent more than two minutes in the bathroom, about 5 percent of their monthly earnings for each penalty.

This labor revolt came a week after about 1,000 workers stood up against riot police in Fengcheng, 475 miles southwest of Shanghai, after going on strike at a factory owned by a supplier for Foxconn International Holdings Limited (HKG:2038), which has been involved in a number of controversies over working conditions.

The Jan. 13 strike at a facility owned by Jiangxi Xin Hai Yang Precision Components was dispersed by the authorities. Several images were posted online of the strike. The workers earn a base salary of about $207 per month, which can double with overtime, according to ITWorld.

Foxconn, a Taiwanese contract manufacturer whose most notable clients include Apple Inc. (NASDAQ:AAPL) and Microsoft Corp. (NASDAQ:MSFT), has been the target of numerous allegations of poor working conditions in China in recent years, including workplace suicides and poor pay and working conditions. In September, about 2,000 workers rioted against company security personnel in response to “work-related” incidents. About 40 people were injured in that brawl.