FORT WORTH, Texas — October used to be scary-movie month.

That was before Halloween spawned a month-long business blockbuster of its own.

"Halloween is a $6 billion industry," said St. Louis haunted house owner Larry Kirchner. "I mean, this is an industry that's almost as big as Hollywood, and it's only one month long.

"We used to consider it the haunted house industry. Now it's the Halloween attraction industry."

Halloween retail spending will rise to $66.54 per person from $64.82 per person last year, with 64.5 percent of Americans planning to celebrate, up from 58.7 percent last year, according to the National Retail Foundation. Its estimate for spending: Nearly $5.8 billion.

And although Halloween retail sales trail Christmas and Thanksgiving, Mother's Day, Valentine's Day, Easter and Father's Day, it still all adds up to what experts call a marketing dream, even in a dark economy.

"Halloween is a celebration that fills the gap between the end of summer and winter holidays," said Debra Laverie, a Texas Tech University marketing professor. "Many consumers will see this Halloween as a way to lighten the mood and have some fun so they can forget about the economy and their investments."

It has gone far beyond costumes and candy. Haunted houses are being joined by pumpkin patches, corn mazes and other rural attractions dubbed "agritainment." And some consumers are spending hundreds of dollars or more to decorate their homes, host parties and buy or rent elaborate costumes.

Michigan-based retailer Halloween USA opened 13 stores in the Dallas-Fort Worth area in 2008, its first year here, marketing manager Any Gajda said. The company also opened five stores in Utah.

The privately owned business is open only in September and October.

"We have everything," Gajda said. "Instead of one witch costume, we'll have 20."

Haunted houses are now recession-proof $1 billion monsters. Even 9/11 didn't hurt business at Kirchner's haunted house. It's in an old 20,000-square-foot St. Louis warehouse.

"My haunted house was set to open three days later," Kirchner said. "I had the best year I've ever had. It was well over $1 million."

That's nothing compared with the $30 million each that Kirchner said Universal Orlando Resort's Horror Nights and Knotts Scary Farms Haunt will take in. Adult admission to the Haunt is $52.99.

In fact, the haunted-house business is so large that it will get its own trade show in March 2009, separate from the folks who sell orange-colored cocktail napkins and less-dramatic Halloween products.

The Transworld National Haunt and Attractions show is scheduled to take place in St. Louis, a convenient location for the estimated 7,000 buyers who want to load up on prosthetic body parts and drive home with their scary wares.

Michael Chaille converted Hollywood expertise into a haunted house career.

Chaille, who runs Ghost Ride Productions, based in Bellevue, Wash., is a supplier of Halloween props that include lifelike severed heads, flayed human torsos and, for $1,899, a high-tech, man-made hog splashed in fake blood that oinks and grunts.

"Our niche is realism," Chaille said. "We don't try to go cartoony. Right now, we have over 60 heads. They start at $99."

Chaille said his customers typically spend $10,000 to $20,000 on animated bodies, glowing strobe-light eyeballs and $589 "man kabobs." At those prices, it's no wonder haunted houses charge what might strike some as spookily high admissions.

"Fifteen years ago the haunted-house industry stepped out on the porch and hollered," said Kirchner, a 20-year industry veteran. Now, "haunted houses are creating their own original horror movie. It's live: you're part of it."

D'Ann Dagen, who runs Hangman's House of Horrors in Fort Worth, is founder and past president of the International Association of Haunted Attractions. She estimates that her haunted house will log about 25,000 paid admissions at $20 each this year. That's not quite at the peak levels of 1997, when there was less competition and she saw 35,000 to 40,000 visitors.

"We're doing quite well this year," Dagen said. "My gut feeling is, we will be even with last year. We could be up 10 percent."

Her operation is in its 20th season.