The prosecution said Sunday it will summon four humidifier disinfectant makers later this month, on suspicion that their products triggered lung damages which resulted in the loss of 143 lives.

The four humidifier disinfectant makers include a leading household manufacturer Oxy Ssak Ssak, Cefu, local supermarket chain Homeplus, and Lotte Mart’s in-house brand Wiselect.

Their products contained polyhexamethylene guanidine phosphate, a chemical known to have powerful sterilizing power compared to other chemicals The substance is restricted in proportion by the Environment Ministry.

Local chemical company SK Chemical, responsible for producing and distribution of PHMG, has also been summoned for investigation.

The probe will focus on finding out whether the firms had taken toxicity tests before sales and whether they were aware of the possible danger caused by inhaling the chemical.

The prosecution will also eye the toxicity of PHMG when inhaled in a powder form. According to Australia-published materials safety data sheet -- created when SK Chemical exported PHMG to Australia in 2003 -- PHMG is “poisonous when inhaled in powder form at room temperature.”

Earlier this year, Seoul Central District Prosecutor’s Office’s special probe team analyzed product properties and tested toxicity of each maker’s humidifier disinfectant, closely looking into the cases of over 170 victims.

The humidifier disinfectant probe was launched back in 2011 after 143, including four pregnant women, died of lung related symptoms with unknown causes.

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