Multinational manufacturer 3M apologized for the uproar over the detection of a toxic substance in its air purifier filters, and promised to start a recall on Friday.

The apology comes after weeks of silence following the first reports of potentially harmful toxins in the company’s filters.

“We sincerely apologize for the concern that we have caused consumers and our client companies over the results of the Environmental Ministry’s investigation announced on Wednesday,” the statement read.

On Wednesday, the Environmental Ministry had announced that it had identified filters that released the toxic substance. On Friday, the ministry released the names of 84 air conditioners and air purifiers that used the problematic filters. All of the filters were manufactured by just two companies: 3M and CNTUS-Sungjin.

The controversy began last month when it was discovered that a substance called octylisothiazolinone, or OIT, was found in the air purifiers of three manufacturers -- Cuckoo, Dayou-winia and LG Electronics -- which all bought the filters from 3M.

OIT’s primary effect is to cause allergic reactions in the skin and eyes, but it can be toxic when continuously inhaled. The substance was added as part of the air freshening effect of the filters, according to the company. 3M says it has stopped production of the relevant products and has begun a recall while maintaining their claim that the levels of OIT are not harmful to the human body.

3M’s apology is unlikely to quell anger here, especially after it became known that Korea was the only country in which 3M sold filters containing OIT. There has been a string of incidents in which multinational companies sold potentially harmful products here.

By Won Ho-jung (hjwon@heraldcorp.com)