TOM KRISHER, AP Auto Writer

DETROIT (AP) — The biggest automotive recall in U.S. history is about to get much larger.

U.S. safety regulators are expected to announce Wednesday that Japanese air bag maker Takata will recall over 35 million more air bag inflators that can potentially explode with too much force and injure people.

This latest action will more than double the size of the existing recall. Automakers have replaced only 28 percent of the 28.8 million inflators that have been recalled starting over two years ago, so the move raises questions about how quickly car owners can expect to get replacement parts.

Takata and other companies have been unable to make new inflators fast enough. Automakers also face difficulty in contacting owners and getting them to take cars to dealers for repairs.