Dutch medical equipment maker Philips on Wednesday said U.S. regulators might have overestimated the number of safety issues raised by customers related to its recall of ventilators in which a potentially hazardous foam was used.

The U.S. Food and Drug Administration (FDA) this month said Philips’ evaluation of health risks was inadequate, as it had found tens of thousands more complaints in the company’s customer database than the almost 1,250 reported by Philips.

“The complaints that were referenced by the FDA are the result of a very broad search. Therefore the complaints did not necessarily relate specifically to the issue that led to the recall,” Philips CEO Frans van Houten told reporters.

Philips in September estimated it will replace up to four million ventilators and respiratory devices because of a polyurethane foam part that might degrade and become toxic.

Philips shares have lost around a third of their value since it announced the recall in April as investors fear the issue will lead to large claims.

They sank to their lowest level since March last year after the FDA on Nov. 12 said it had found new issues at the Dutch company’s manufacturing facility.

Van Houten said Philips was looking closely at all the questions raised by the FDA, and would closely investigate the number of complaints the regulator found.

“Not all entries in the database actually are a safety issue or a defect,” Van Houten said.

“Together with the FDA we have to go through the details and demonstrate what is related to the particulates and what were innocent queries.”

Philips has so far put aside 500 million euros ($560 million) in provisions for recall costs. In October it lowered financial forecasts for the year, citing fallout from the recall and related lawsuits.

($1 = 0.8925 euros)