The weeks before Halloween are a busy season for Wal-Mart's little-known trust and safety compliance team.

Their job is to come between the 40,000 costumes sold on the retail giant's sprawling website and the 140 million shoppers who might be offended by those costumes.

In a win for the team, Wal-Mart customers haven't been able to purchase the white hotpants and wig marketed as a Caitlyn Jenner transgender parody costume. A decapitated Cecil the Lion head sold with a dentist's smock? Banned on Walmart.com.

Don't expect to see the gratuitously distasteful costume meant to invoke the dispute between Fox News anchor Megyn Kelly and Donald Trump. Nor a sex-themed vampire suit sold under the name Down for the Count. Those were low-hanging fruit.

"We want Halloween to be fun and to be a surprise. But we don't want to belittle serious incidents," said Bao Nguyen, head of media relations for Wal-Mart Global eCommere in San Bruno, Calif., where a dozen employees take the lead on hunting down offensive products. "We do not want to offend anyone, especially during Halloween."

The Wal-Mart compliance team doesn't simply react whenever a product provokes a public backlash. Each day, often with Nguyen's help, the group scours headlines and online products to identify items that might become newly offensive in light of the day's news.

It's a responsibility that extends beyond Halloween. Nguyen says the team was among the first to begin pulling items depicting the Confederate flag in June after the gunman who killed nine worshipers in a black church was seen displaying the flag on social media.

As the retailer beefs up its website to take on Amazon.com, it's increasingly reliant on third-party vendors-and exposed to the perils of the wide-open Internet.

Walmart.com has burgeoned from 2 million items in 2012 to 7 million items today, a vast universe of potentially insulting products compared to the 500,000 things displayed at a brick-and-mortar Super Store. That means the compliance team often fails to preempt public scorn.

Just this week, for instance, a children's costume depicting an Israeli soldier earned negative headlines for Wal-Mart.

The team also whiffed this season with Little Amigo, a costume modeled by a little white boy in a sombrero, poncho, and simulated mustache. A huge, fake "Arab" nose also slipped through. These items were speedily removed from Walmart.com soon after customers complained.

"I've been doing this for 15 to 20 years and there's always something that slips through," said Scot Wingo, chairman of e- commerce consultant ChannelAdvisor. His company works with about 50 online marketplaces and uses image-recognition software to help spot mislabeled items that might get past censors.

Major online retailers take different approaches to the growing demand to shock or titillate during the $7 billion Halloween sales season. Little Amigo, Caitlyn Jenner, and the Israeli soldier remain available on Amazon.com and eBay.com, alongside other sites. Wingo said companies tend to differ on whether an item is offensive or simply provocative.

EBay, like Wal-Mart, moved to ban Confederate flags from its inventory of 800 million items, said Mike Carson, senior manager of regulatory policy at the auction website. The eBay team in San Jose charged with compliance ended up eliminating 25,000 items. Anything that slips past the monitors might be spotted by social-media backlash or complaints to customer service teams around the world.

But eBay appears to have no problem with some of the costumes yanked by Wal-Mart, as long as the language describing the item isn't offensive. The Arab nose is gone, but many Arab Sheik costumes are available. So is the Israeli soldier outfit and the vampire sex costume.

Amazon, for its part, offers plenty of costumes that don't need to be associated with news events to become provocative. A search on the website for a costume inspired by male anatomy shows that it's available in 45 colors and patterns, including pink and green. Amazon declined to comment.

Halloween costumes this year will make up about 65 percent of holiday spending, according to September estimates from the National Retail Federation.

This year, the trade group found in a survey, more people will attend a Halloween party than take their children trick-or-treating.

As the occasion has become an adult holiday, the desire to add sexuality and controversy has grown, said Kit Yarrow, a consumer psychologist who has studied Halloween spending patterns for 15 years. And, of course, controversy sells.

"PC takes a holiday for Halloween," said Yarrow.