A LEADING Chinese drugmaker in the country's northeast has been exposed as having released pharmaceuticals into waterways and improperly burning medical waste, causing serious water, land and air contamination.

Emissions from a factory operated by Harbin Pharmaceutical Group Co, China's second-biggest drugmaker by market value, contained hydrogen sulfide levels more than 1,000 times the permitted amount, according to a China Central Television investigation.

The colorless but poisonous and flammable gas, which has a strong odor of rotten eggs, forced people in or near the factory to wear masks, while residents living nearby had to keep their windows closed all year round, the report said.

The gas, the result of the production of penicillin at the factory in Harbin, Heilongjiang Province, was released into air without any processing, it said.

In addition to the foul smell, hydrogen sulfide can cause headaches, eye irritation, sore throat, cough and nausea, although it most seriously affects the nervous system.

In tests two years ago, the amount of hydrogen sulfide in places close to the 53-year-old factory was 1,150 times the maximum permitted by the national standard while that of ammonia, a caustic and hazardous gas with a characteristic pungent odor, was 20 times the standard, the report added.

Waste from the production of penicillin was also released into a nearby creek, giving the water a yellow tinge.

The concentration of ammonia nitrogen at water near the sewage outlet was almost three times the maximum allowed under the national standard, the report said. The amount of organic compounds in the water was 1,180 milligrams per liter, 10 times the permitted level.

An unnamed worker told a CCTV reporter that the factory's water treatment equipment had been under repair for more than a month, meaning that all waste was directly pumped into the waterway.

A makeshift incinerator was found alongside the creek bank, with garbage, unwanted drugs, leftover chemical raw materials, hydrochloric acid and sulfuric acid all burning inside and releasing fumes into the air, the report said.

Neither local environment protection authorities nor the pharmaceutical company have commented on the television program which was screened yesterday.

The company makes annual sales of more than 5 billion yuan (US$772 million), according to its website.

Last week, the Ministry of Environment issued a report saying that more than half of China's cities are affected by acid rain and one-sixth of major rivers are so polluted the water is unfit even for farmland.

The waters off Shanghai, Tianjin and Guangzhou were rated severely polluted, with only stretches around the resort island of Hainan and parts of the northern coast given a clean bill of health.