Pacific Engineering and Production Co., with the help of a Utah-based customer and the federal government, will rebuild its ammonium perchlorate plant leveled by a series of May 4 explosions, officials say.

The company is arranging $33 million in bank loans that will be retired from "sales, profits and cash flow," President Fred Gibson said Monday. The federal government, he said, will retire any unpaid balance after seven years.A spokesman for Morton Thiokol in Brigham City, Utah, said Monday the aerospace firm had been designated as an agent to help PEPCON return to full production.

The plan apparently calls for the government to pay Morton Thiokol, a user of ammonium perchlorate, higher prices for its solid rocket fuel as a method of directing more money into rebuilding PEPCON and expanding an adjacent company.

Ammonium perchlorate is a vital ingredient in solid rocket fuel that powers the space shuttles' booster rockets made by Morton Thiokol and many of the nation's missiles.

Shortly after the PEPCON plant blew up, Gibson blamed the disaster on a ruptured natural gas line. The cause is still being investigated by the Clark County Fire Department.

Southwest Gas Co. has denied Gibson's allegation, saying the utility was a victim of the disaster, not the cause. But Gibson said legal action is being planned by

PEPCON in an attempt to recover its losses.

"We expect in the near future to assert a substantial claim for the company's losses," said Gibson.

Gibson told a news conference four days after the explosion that PEPCON was broke and carried only $1 million in liability insurance.

The destruction of the PEPCON plant and the resulting shortage of ammonium perchlorate has threatened to reduce the number of space-shuttle missions from nine to seven in 1989, according to NASA officials this week.

NASA and the Pentagon announced several weeks ago the government will spend more than $90 million in surcharges to help rebuild PEPCON and expand the neighboring Kerr McGee plant.

The two Henderson, Nev., plants, located a mile apart, were the sole domestic producers of the chemical. Kerr McGee produces up to 36 million pounds of ammonium perchlorate annually - less than half of what PEPCON was turning out before the May 4 disaster.

Gibson said the PEPCON plant would be rebuilt outside the populated Las Vegas Valley. He said one site being considered is 60 miles northeast of Las Vegas.