A group of people victimized by toxic humidifier sterilizers plan to bring a class-action lawsuit against the products’ manufacturers and distributors to seek unspecified damages, an environment civic group said Thursday.

The Seoul-based Asian Citizen’s Center for Environment and Health said it will convene a meeting of the victims and their families on Sunday to discuss the planned lawsuit and form a group of litigants for the lawsuit.

The lawsuit will be filed by the victims who have yet to sue individually to seek compensation. The companies targeted are British firm Oxy Reckitt Benckiser, Lotte Mart and other domestic and overseas companies involved in the manufacturing and distribution of the products in question.

“We will discuss the amount of the damages with them if (the class-action lawsuit) is formalized at the meeting,” said Lim Heung-kyu, an official at the center. “We will try to make the group of litigants as large as we can.”

   The humidifiers disinfectant case, one of the worst scandals involving consumer products using chemicals, came to light after four pregnant women died of lung problems for unknown reasons in a row in 2011.

The authorities have said there is a connection between the deaths of more than a hundred people who died from lung failure and the germicides they used in sterilizing household humidifiers.

The prosecution alleged that the two chemicals used in the products — PHMG Phosphate or PGH, were responsible for severe illnesses and deaths. Two other chemicals used were PHMG hydrochloride and MIT/CMIT, which the prosecution found not as harmful as the other two.

A tally compiled by the civic group said the number of victims, including 228 dead people, from the humidifier sterilizers has stood at 1,528.

 Family members of people victimized by toxic humidifier sterilizers and civic group members attend a press conference at a Seoul hotel on April 18, 2016, that Lotte Mart, a major retail giant in South Korea, held to apologize to its customers. The retailer promised compensation for any damage that its humidifier sterilizer might have caused.

On Monday, Lotte Mart and Homeplus, major retail giants in South Korea, apologized to their customers, promising compensation for any damage that their humidifier sterilizer might have caused.

Civic and customer rights groups, however, doubted the sincerity in the apologies and compensation promises, claiming that the timing is suspicions in that they came too late and also just before the prosecution’s imminent move to summon their officials.