Four-year-old Rory McDermott got a Croc-clad foot caught in an escalator in August at a mall in northern Virginia. His mother managed to yank him free, but the nail on his big toe was almost completely ripped off, causing heavy bleeding.

At first, Rory's mother had no idea what caused the boy's foot to get caught. It was only later, when someone at the hospital remarked on Rory's shoes, that she began to suspect the Crocs and did an Internet search. "I came home and typed in 'Croc' and 'escalator,' and all these stories came up," said Jodi McDermott, of Vienna, Va.

"If I had known, those would never have been worn."

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Japan has asked the maker of Crocs to look into changing the design of its footwear after complaints that children wearing the colorful plastic clogs have had their feet injured on escalators.

The Trade Ministry said Friday it issued the warning after receiving 65 complaints about Crocs and similar products getting stuck in escalators between June and November last year. Most of the cases involved small children.

At rail stations and shopping malls around the world, reports are popping up of people, particularly young children, getting their toes caught in escalators. The one common theme seems to be the clunky soft-soled clogs known by the name of the most popular brand, Crocs.

The Washington Metro — one of the nation's largest transit systems — has even posted ads warning about such shoes on its moving stairways. The ads feature a photo of a crocodile, which is the company logo, though the signs don't mention Crocs by name.

There are reports from Singapore to Virginia of instances in which children have had toe nails, and even toes, torn off while wearing Crocs-style shoes on escalators.

In Singapore, a 2-year-old girl wearing rubber clogs — it's unclear what brand — had her big toe completely ripped off in an escalator accident last year, according to local media reports.

And at the Atlanta airport, a 3-year-old boy wearing Crocs suffered a deep gash across the top of his toes in June. That was one of at least seven shoe entrapments at the airport last year, and all but two of them involved Crocs, airport officials said in September.

Crocs pointed out that the Japanese government also asked the escalator industry to improve awareness about safety issues.

"The ministry found that there were a number of factors that led to a specific incident in Japan last summer," said Crocs spokeswoman Tia Mattson. "Those included escalator maintenance, footwear and user riding behavior, which they determined was the primary cause of the accident. We continue to be supportive of escalator safety initiatives and we will consider any recommendations the ministry has for footwear manufacturers."

Recent tests by the National Institute of Technology and Evaluation confirmed the spongy footwear can easily get stuck in escalators because of its flexibility and grip, Japan's Trade Ministry said.

The ministry urged supermarkets, railway stations and other commercial facilities to upgrade signs to urge escalator riders to use caution.

The Japanese unit of Crocs has published a statement on its official Web site warning customers to use caution when riding escalators.

About 3.9 million pairs of Crocs footwear were sold in Japan last year, the ministry said.