Ordinarily the two words on most Louisvillians' lips this first week of May would be "Kentucky" and "Derby" or "Settle" and "Slew."

Not this year.

For the past several weeks, Louisvilles collective mind has been in the sewer. The two words heard most frequently from downtown Walnut Street to the suburbs outside the Waterson Expressway are "hexachlorocyclopentadiene" and "octochlorocy clopentadiene."

They are known as "hexa" and "octa" for short and they are toxie chemicals that have infected local sewer lines for nearly a month. Tons and tons of the poisoned sludge have been hauled to a landfill in Wilsonville III. The toxicity has been compared to phosgene a poison gas used during World War I.

Residents of Wilsonville have foul to no avail.

The gritty problem has had only one beneficial side effect. With all the talk of hexa and octa, the No. 6 and No. 8 horses figure to receive a larger-than-life play in the Derby betting Saturday.In New York OTB they are a cinch exacta.

Otherwise, Louisville and the 103d Derby offer few supplies this week. The buildup began with the running of the Blue Grass Stakes at Keeneland in Lexington last Thursday. The "Kentucky Derby Festival" than takes over offering parades concerts a balloon race, a steamboat race on the Ohio, a cycling race, even a minimarathon for distance runners to whom a mile and a quarter is a wind-sprint.

"The aim has been to develop a week's entertainment aimed at family fun," says Jack Guthrie, executive vice president of the Festival Committee. "Horse racing is basically a man's sport. We want Dad to bring the wife and kids along."

Getting to Louisville and having an enjoyable experience here during Derby Week is easy, with a little planning.

"Start writing to hotels early in January, when they begin compiling their waiting lists." Guthrie suggests."The three-day rate (Thursday, Friday and Saturday nights) ranges from $60 to $275 or more at the Galt House or Executive Inn. I also recommend, for those who make up their mind to come late, that they look into accommadations in Lexington or Bowling Green. They're 100 miles away, but the expressway system is excellent and Lexington's in the heart of the breeding country."

Rooms in boarding houses often are available. Check the classified ads in the Courier-Journal or Times, or place one yourself.

"The young people and college kids can flow with the punches," Guthrie said. "For adults trying to make do at the last minute, it's difficult, although it never hurts to check with any hotel at the last minute. Some rooms do open up as we get down to the wire, through cancellations.

The biggest problem each year is getting seats.

"There are no seats available," Guthrie noted. "All of them are on a renewal basis. The lowest price is $16 to $2.400 for a 16-seat table in the Skye Terrace." For $10 you can get in the infield or grandstand areas and there are plenty of these tickets available. But they are no bargain at the price.

"You need a shoe horn to get into the Downs," Guthrie warned. "Large corporations have some tickets available for their friends. You're best shot, for the average fan, is to make a contact in the hotel or motel after you arrive; the bellop or the desk personnel. Scalpers do have tickets, and by Saturday morning they often begin getting a little scared.

"The important thing is to have patience to willing to wait until 10 or 11 that morning. The race isn't till 5:30. You can't sit in your room and hope the phone will ring, but if you move around a little I know many people who get tickets tht way for $20 or so."

A racing fan should go the Downs on Derby Day - once, although 80 per cent of the 120,000 fans who will attend Saturday have poor to atrocious viewing for the race. The first question most spectators ask is, "Who won?"

But the 45 minutes leading to the actual running ar exciting. The horses come from the barn area to the main track to get to the saddling area, and when the first horse leaves the paddock and the bands begin to play "My Old Kentucky Home" you'll be glad you overcame the traffic and all the other headaches to be here - once.

The second time, knowing what to expect, you have only yourself to blame if the experience doesn't seem worth it.

Entries will be taken for the Derby this morning. Nostalgia and Kodiack are questionable. The 14 horses considered firm starters are Seattle Slew, the entry of Run Dusty Run and Bob's Dutsy. For The Moment, Giboulee, Steve's Friend, Affiliate, Western Wind, Sanhedrin, Flag Officer, Best Person, Get The Axe, Papelote and Sir Sir.