The State Post Bureau issued urgent safety reminders to express delivery businesses on Sunday, after a man was killed and nine others sickened by parcels that carried toxic chemicals.

In a statement on its website, the bureau reiterated that all postal and delivery companies must have their couriers inspect parcels in front of the senders.

Various checks will be conducted to ensure that delivery companies follow rules and refuse clients who do not let couriers check parcels, or decline to offer requested documents and identification.

Postal and delivery companies could face severe penalties for failing to comply, including suspending business operations and revoking their business licenses, the bureau said.

Media reported last week that Liu Xingliang, a man in Shandong province, died on Nov 29 after receiving a pair of shoes delivered by YTO Express Co, a private delivery company in Shanghai. Nine others - Liu's two family members, five deliverymen and two recipients - had been sickened by contaminated parcels delivered by the same company.

Investigations found that 154 parcels in the same vehicle had been contaminated by a parcel containing toxic chemicals from Hubei province, the Shandong postal bureau said.

On Saturday, the head of a chemical plant in Hubei, surnamed Yang, was detained by police. He was transferred to Shandong province on Sunday for further investigation.

Police found that on Nov 27, Yang's factory plant, a branch of Jingmen Xiongxing Chemical Co, sent samples of methyl fluoroacetate, a highly toxic chemical, to a medicine factory in Shandong province through a YTO-affiliated company.

Methyl fluoroacetate is on the list of substances that cannot be delivered, according to regulations. But the chemical plant claimed it was safe when giving it to the express company.

According to a police release, a deputy head of Jingmen Xiongxing Chemical Co who was identified only by his surname, Huang, admitted that it was the third time that the plant had sent methyl fluoroacetate through the delivery company.

YTO apologized on its micro blog on Saturday to the victims of the case, and said it will use a legal process to protect its own interests as the chemical factory did not tell the truth of sending toxic chemicals.

Its staff had performed routine checks "according to company rules", it said. Even after YTO found the leakage and informed the chemical company of the leakage, the chemical plant claimed that the delivered parcel was nontoxic and harmless, YTO said on Saturday.

The YTO-affiliated company in Weifang in Shandong that was responsible for the delivery was fined 28,000 yuan ($4,610) by authorities.

The case has spurred worries among consumers. In China, an increasing number of people shop online, and their orders are delivered by couriers. In 2012, the country's express delivery companies delivered 5.7 billion parcels, an annual increase of 33.7 percent.

Yue Shenshan, lawyer and partner at Beijing Yuecheng Law Firm, said that in this case, the person who was responsible for the chemical plant is suspected of negligent homicide, as the company should have known the dangers of the parcel but denied what was delivered after the leakage.

The delivery company should also be punished as in this case, the delivery of dangerous items has had serious consequences, he said.

Contact the writers at jinhaixing@chinadaily.com.cn