WASHINGTON — A California company has voluntarily recalled 100,000 portable crib-playpens of a type that have collapsed unexpectedly at least four times, killing two babies, the Consumer Product Safety Commission said Wednesday.

Two other babies were revived after they stopped breathing when their Home and Roam or Baby Express playpens collapsed.

The playpens can appear to be set up properly even when their top rails are not locked completely into place, the commission said. Unless the rails are locked, a baby can be caught by the neck and strangled.

The playpens, manufactured by Baby Trend Inc. of Pomona, Calif., come in a variety of colors and three sizes: 40 by 40 inches, 40 by 28 inches, and 31 by 41 inches.

The words “Home and Roam” or “Baby Express” and “Baby Trend” appear on two of the four top rails. The playpens cost from $60 to $130.

About 100,000 were sold from 1992 to 1994 by several retailers, including Kmart, the commission said.

“Baby Trend is recalling all Home and Roam and Baby Express crib-playpens, regardless of the purchase date or warning labels,” the commission said in a written statement.

Consumers were being advised to call the company at 800-234-1879 to have their top-rail locks replaced free. The new lock is designed to prevent collapse.

“With the old ones, you couldn’t see and you couldn’t hear whether it was locked into place,” said Kathleen Begala, a commission spokeswoman. “You will hear a distinctive click with the new ones. You will definitely know it’s locked.”