BEFORE you expend considerable effort, check out the trail schedule for Hashers in your area and see if they are laying a trail starting anywhere within a few miles of the mysterious powder you are investigating. 

There are HHH groups in most large cities and they are also commonly found near US, British and Australian military bases. This page is written by the founder of the Southern Comfort Hash House Harriers, a group based near Fort Gillem in the Atlanta surburbs since 1994 and a "sister Hash" of in Japan. .

The Columbian Hash House Harriers group runs every first and third Sunday afternoon, and like many others, tries to inform the local police and emergency (911) dispatchers about their trails... to help ward off emergency responses to citizens' fears over handfuls of anthrax, cocaine or some other suspected harmful substance. 

Usually trails are laid in white bread flour, a mixture of flour and sawdust, or flour colored with chalk. In woods or rough terrain, trails may include strips of toilet paper or handfuls of shredded paper. Some sample Hash trail markings are as follows:

There are many combinations and variations of the above markings, including triangles and other shapes. The letters "YBF, QZ, BN, SV, SC and CB" are also common. 

Trail markings are used by the Hare laying the trail to communicate with the Pack of Hounds or Harriers trying to follow the trail. 

Cypriot firemen in special protective suits shovel up specimens of white powder found in Nicosia municipal gardens. The substance later turned out to be flour markings left by a local running club to indicate a trail. (REUTERS/Andreas Manolis, Tuesday Oct. 16, 2001)

Phoenix police and firefighters will remember it as "the Mystery of the White Powder." 

The call came about 10:30 a.m. Monday. A citizen alerted the Phoenix Fire Department that Daisy, his golden retriever, became ill after eating white powder off a sidewalk in the Moon Valley area, near Ninth Avenue and Thunderbird Road. 

"The man told us his dog sniffed and licked the stuff and came back in the house and vomited," Division Chief Terry Garrison said. "The guy put two and two together and figured there might be something very wrong with that white powder." 

The firefighters hit the street. Those first at the scene found a daunting sight: White powder all through the neighborhood. 

It was deposited in odd, arrowlike stripes on the sidewalks, and a breeze had apparently scattered it onto lawns and landscaping stones. 

"Our people said, 'Hey, this could be hazardous material. We better take some precautions,' "Garrison said.

The fire department sent 12 big fire engines to the scene, carrying a total of about 60 firefighters. 

The Phoenix Police Department sent eight motorcycle officers, one motorcycle sergeant, one motorcycle lieutenant, two field officers, one field sergeant, one detective and a public information officer, a spokesman said. 

The cops closed off an area of about 2 square miles. Children at the local elementary and middle schools were kept inside. Neighbors were warned not to get near the mysterious white stuff. 

Some firefighters gathered samples of the powder. Most sat for hours under the shade of trees and firetruck umbrellas, navy blue T-shirts soaked with sweat from the 106-degree heat. 

Some chatted with nearby golfers. 

Some complained. 

Many cheered when the fire department's "goody" truck showed up, stocked with fresh Gatorade and trail mix. 

One local resident emerged from his house, gazed around in wonder, and asked police who had been murdered. 

Television news reporters reported the white powder crisis as their 5 p.m. lead story on at least two stations. It led the 10 p.m. news on most stations. 

The fire department called in a hazardous-material company to vacuum up the substance. Children were removed from harm's way and driven home on buses or by worried parents. 

Finally, at 11 p.m., the six men operating the huge vacuum cleaners were finished. The firefighters and the cops packed up and departed. Residents went to bed. 

And as they slept, an anonymous caller to the fire department solved the mystery of the white powder. Garrison said it was a woman who declined to leave her name. 

"She said she was with a jogging club, and they had put flour on the sidewalks Saturday to mark where people were supposed to jog in an event they had," Garrison said. 

"She said she was real sorry, and hung up."