Police and federal investigators yesterday found several elements they said are used in the manufacture of the drug PCP in a Northeast home where three men, including two off duty D.C. policemen were seriously injured in an explosion and fire Sunday night.

One of the officers, Walter McKenzie, remained in critical condition at Washington Hospital Center last night with second and third degree bruns over 75 per cent of his body.

The other two men, officer Charles Lynch, 31, and Percy Evans of 1404 25th St. SE, were listed in serious condition with burns at the same hospital.

The blast occurred in McKenzie's home, according to police.

Fire marshalls have determined that the explosion occurred in the kitchen, apparently on top of agas stove. The kitchen was completely gutted by the blast and fire, which was extinguished before it spread.

Armed with a search warrant, investigators from the Drug Enformcement Administration and the D.C. police homicide and narcotics squads searched the house yesterday and found parsley leaves and a quantity of ethyl ether and a second chemical, according to police sources.

They said two chemicals are ingredients of PCP, which is commonly wrapped in parsley leaves and smoked. Ethyl ether is highly flammable and could explode if not kept at the correct constant temperature, investigators said.

PCP (Phencylidine), is a potent hallucinogn that has become popular with young people who believe incorrectly it is less harmful than LSD or ampheamines easy, but dangerous to make, PCP can lead to paramoia, numbness, schizophrenic symptoms and violent outbursts, medical authorities say.

The drug is known on the street as "Angel Dust," "Killer Weed," and "Wobble Weed."

The police internal affairs division is investigating, and the two officers have been placed on administrative leave with pay, pending completion of the proble, officials said.

McKenzie, 36, and Lynch, who lives in Adelphi, Md., are nine year veterans, described as friends who attended the police training academy together. Both work in the 4th police district, McKenzie in a scout car and Lynch as a crime scene search officer.

The Washington area has become known as a center for PCP manufacture. Agents, smashing homemade operations, have made a number of arrests in homes and on farms in the last two years.