Household products manufacturer Oxy Reckitt Benckiser allegedly destroyed evidence related to humidifier disinfectant blamed for the loss of some 140 lives, when the prosecution launched a probe in late February, prosecutors said Wednesday.

The Seoul Central District Prosecutor’s Office said that the firm is suspected of deleting a number of materials and safety data sheets written from 2001 to 2011 and created by a local chemical company SK Chemical.

The prosecution is set to summon product researchers from Oxy Reckitt Benckiser and ask why the data sheets were destroyed in bulk, under the possibility that the move was intended to hide the product’s toxicity level.

Since 2011, SK Chemical has been responsible for the production and distribution of polyhexamethylene guanidine phosphate, one of the chemicals contained in the humidifier disinfectant. PHMG is a chemical known to have powerful sterilizing power compared to other chemicals. It is restricted in proportion by the Environment Ministry.

According to the materials safety data sheet that was created when SK Chemical exported PHMG to Australia in 2003, PHMG is “poisonous when inhaled in powder form at room temperature.” The report also warns that the chemical should not be consumed by a human.

On Monday, Lotte Mart, one of the manufacturers of disputed humidifier disinfectant made an official apology, vowing to provide due compensation to the victims and their families.

The announcement marks the first ever public action taken by a maker of the toxic disinfectants since the probe was launched in 2011. The prosecution has started to summon officials of related companies including Lotte Mart, Oxy, Cefu, and Homeplus.

By Kim Da-sol (ddd@heraldcorp.com)