Four companies were named and "blacklisted" on Wednesday by China's environment watchdog for failing to correct wrongdoings uncovered in an earlier inspection.

The Anshan Steel Group Co. Chemical General Factory in northeast China's Liaoning Province has not halted trial operation of a technical upgrade project as required by environment authorities and has emitted a large amount of pollutants, according to the Ministry of Environmental Protection.

The Harbin Linen Textile Co. in Heilongjiang Province refused to stop production and pay a fine after one of its projects was found to be operating without approval.

One copper company in Guangxi has not corrected its management of dangerous waste, and a sewage treatment plant in Anhui has not been put into use due and has done nothing to change the situation.

Environment authorities inspected 93 major companies in 2012 and conducted a follow-up check on their corrections and punishment earlier this year.

The four companies were the only ones found to have taken no measures to correct their violations in environmental protection, according to the ministry.

Ministry official Zou Shoumin said that the heads of the four companies would be transferred to supervision authorities.