A 36-year-old District man was sentenced yesterday to 45 years in prison without parole for manufacturing 240 grams of pure PCP worth nearly $1 million.

The sentence was one of the first imposed here under a 1986 law that provides for stiff mandatory minimum sentences for repeat drug offenders and is one of the longest ever imposed here on a drug defendant.

U.S. District Judge John Garrett Penn handed down the sentence for Thomas E. (Chuckie) Dorsey, 1343 Irving St. NW, who was convicted Nov. 9 of manufacturing more than 100 grams of PCP and conspiracy to manufacture PCP.

Penn said during the sentencing that he was especially concerned about the long-term impact of PCP on young people, who have made it one of the most popular street drugs in the area.

Statistics compiled by the D.C. Pretrial Services Agency show that 45 percent of all persons arrested on criminal charges in October tested positive for PCP.

PCP is a synthetic drug that affects the section of the brain that controls the intellect and keeps primitive instincts in check. Users may experience fury, paranoia, irrational behavior and a sense of superhuman strength.

A variety of exceptionally brutal crimes has been attributed to people under the influence of the hallucinogenic drug.

Dorsey and his codefendant, Tyler N. Haynes, 41, operated their PCP lab -- described as one of the largest in the area -- in a convalescent home on G Street NE, Assistant U.S. Attorney John P. Dominguez said in an interview.

He said law enforcement authorities had been investigating the operation for several years, finally cracking it through the efforts of an undercover agent from the U.S. Drug Enforcement Administration, Thomas Polhemus, who won the trust of Haynes and Dorsey and infiltrated the lab.

"We're rather excited" about the conviction and sentencing, Dominguez said.

"This is the paradigm case. You can't get any better than to pull down a clandestine lab . . . . When you get an operation that busts up a lab, you've cut it off at the source. That's the objective."

Testimony presented at trial showed that in the 14 months before their arrest, Dorsey and Haynes, of 900 G St. NE, had acquired chemicals that could have been used to manufacture as much as $30 million worth of PCP.

Haynes is to be sentenced Jan. 20.

Dorsey and Haynes were arrested last Dec. 30 and have been jailed since their conviction after a six-week trial.

At the time of his arrest, Dorsey had just been released on parole for a 1981 conviction of manufacturing PCP.

"Both defendants have clearly devoted their lives to criminal conduct, both show no likelihood of ever rejecting criminal conduct as a way of life despite prior periods of incarceration, and both were engaging in the manufacture of PCP for purely monetary reasons," Dominguez said in a sentencing memorandum filed with the court.

The new statute, which sets a mandatory minimum jail sentence of 20 years for repeat drug offenders, allows only 56 days per year for "good behavior credit," meaning that Dorsey would have to serve about 37 years before he could be released.

Although U.S. District Judge Oliver Gasch sentenced defendant Garry Jordan to 60 years in jail on PCP charges last year, Jordan will be eligible for parole after 20 years.