For the past month, Cape Girardeau police officers have been carrying little vials of granulated chemicals which can determine whether the person they have stopped is driving while intoxicated.

The Missouri Safety Center, located on the campus of Central Missouri State University in Warrensburg, selected Cape Girardeau as the test site for the new DWI field test units.

"Every officer in the department carries them," said Sgt. Carl Kinnison of the Cape Girardeau Police Department. "Also, the 25 Missouri State Highway Patrol Troopers with the most DWI arrests are carrying them, too."

The units are plastic vials about two inches long filled with yellow crystals.

To "activate" the test, the officer must apply pressure to the center of the tube, causing an inner layer to break. The person under suspicion then is asked to blow into one end of the tube for 10-12 seconds.

If the alcohol level in the person's bloodstream is above .10 the legal limit the crystals will turn blue about a minute afterward.

"I use it as a final field sobriety test," said patrolman David Felton. "But I really place more reliance on my other field sobriety tests."

Felton works a DWI patrol shift one or two times a month. He said he has used the new units on two or three occasions, but only when he was almost positive that the person was over the legal intoxication limit.

"The new units only allow the officer to determine if the person is over the legal limit," he said.

"That is assuming that he or she has not had anything to drink immediately prior to the test."

Officers must wait at least 15 minutes after stopping a driver before administering the new test, Kinnison said.

"If you took a drink (of an alcoholic beverage) right now and blew on one of these, it would turn blue," Kinnison said. "But according to the manufacturer's tests, if used correctly they are very accurate."

The waiting period for the field test is the same as is required for an accurate reading from the state-certified breathalyzer machine at police headquarters.

After a person is arrested for driving while intoxicated, the officer asks the suspect a series of questions. This allows an adequate amount of time for recently consumed alcohol to be ingested into the bloodstream and to leave the mouth and throat.

The vials cost about $1 apiece and can be used only once. The Cape Girardeau police currently have two hand-held breathalyzer units which are used by DWI patrolmen. Each costs about $400.

"The two portable units figure the level of intoxication down to the hundredth," Kinnison said. "But we can't afford to have one for every officer.

"(The new units) can be used by any officer at any time when they are not 100 percent sure that a person will blow above a .10 at the station," he said.

Every time an officer uses a vial, a postcard attached to the unit must be filled out. The card asks about the officer's probable cause in pulling over the subject, the field tests administered and asks for the reading from the standardized breathalyzer at the police department.

"We'll be testing the units for about three months," Kinnison said. "After that, the Missouri Safety Center will do its final analysis and see if they want to use the units throughout the state."