UPDATE 3-U.S. FDA labels Philips expanded ventilator recall as most serious

(Adds Philips response in paragraphs 4 and 8)

Jan 26 (Reuters) - The U.S. Food and Drug Administration (FDA) on Wednesday classified an expanded recall of certain ventilators by Philips late last year as Class 1, or the most serious type, saying they could lead to injuries or death.

The Dutch medical equipment company initiated the recall of 215 Trilogy Evo ventilators and 51 repair kits in the United States in December due to potential health risks from a type of foam used in the devices.

So far, there have been no reported injuries or deaths from the products, which were distributed in the United States and Korea, the FDA said.

"We have already reached the majority of affected customers and we will correct this issue via a repair (replacement of the foam) on site in the coming months" a company spokesperson said in an emailed statement to Reuters.

This is the latest recall by Philips to be labeled Class 1 after it pulled back up to 4 million breathing-aid machines last year amid concerns that a polyurethane foam used in the devices could degrade and become toxic.

Earlier this month, the company raised that estimate by 1 million.

A Philips supplier had incorrectly used a type of polyurethane foam, which is intended to reduce sound and vibration, in one of the parts of the Trilogy Evo ventilators - an issue that was identified during lab testing, the regulator said on Wednesday.

The supplier used polyester-based polyurethane foam instead of a polyether-based one which is specified for these products and meets all applicable standards, Philips said in the email.

The polyester-based foam could break down and potentially enter the device's air pathway, leading to the user inhaling chemicals or other harmful materials, the FDA said.

($1 = 0.8880 euros) (Reporting by Amruta Khandekar; Editing by Devika Syamnath and Sriraj Kalluvila)