At least 185 people in the Netherlands are considering legal action against Philips after developing health problems while using the company’s sleep apnea ventilators.

The Eindhoven-based electrical giant is having to replace 5.2 million machines worldwide after patients were found to have inhaled harmful chemicals during use.

In October SAP Injury Lawyers, based in Amersfoort, said it was representing four Dutch patients who claimed the ventilators had damaged their health.

Another 100 patients have since joined the group action, while two other firms, DAS and Achmea Rechtsbijstand, have around 40 clients each in the case, the Financieele Dagblad reported on Tuesday.

Philips is also facing claims from thousands of affected patients in the United States, with the total cost potentially running into billions.

Last week the company’s share price dropped by more than 15% in a day after it estimated the cost of recalling and replacing the faulty machines would amount to €225 million.