LAS VEGAS, Nev. (AP) _ Production of a critical ingredient for solid rocket fuel resumed today at a Kerr-McGee Corp. plant, five weeks after explosions destroyed the only other plant making the chemical a mile away.

Workers began production after 7 a.m. of the chemical, ammonium perchlorate, which provides the oxygen necessary to burn solid fuel in the booster rockets on the space shuttle and in some military rockets.

Plant spokeswoman Annita Bridges said workers will be on the job around the clock in three shifts as the plant in nearby Henderson gears up to operate at its capacity of 36 million pounds of the chemical a year.

Officials of the National Aeronautics and Space Administration said last week that they had enough of the chemical on hand to fill eight shuttle boosters, enough for four flights. Each set of boosters uses 1.7 million pounds of ammonium perchlorate.

Kerr-McGee officials agreed last week to abide by a list of safety demands from the Clark County Fire Department, Fire Chief Roy Parrish said at a news conference Saturday.

The agreement was announced by Parrish and Bill Curran, chief of the civil division of the county's district attorney's office.

However, public safety officials continued to disagree with Kerr-McGee executives over the safest way to store ammonium perchlorate, a highly explosive fuel oxidizer used in the space shuttle and military rockets.

Kerr-McGee officials didn't attend the news conference and telephone calls to the plant over the weekend were not answered.

Kerr-McGee agreed to temporarily halt its production of ammonium perchlorate after a series of thunderous explosions May 4 killed two people, injured 326 and caused an estimated $73 million in damage at the Pacific Engineering and Production Co. in Henderson.

Alarmed county officials had considered pursuing legal action to prohibit Kerr-McGee from resuming production, but an attorney said the county had no legal basis for such a move, county spokeswoman Lisa Godwin said.

''The county didn't want to shut Kerr-McGee down, but we wanted to ensure in one way or another that there is no potential danger for the people in the area,'' Ms. Godwin said.

Kerr-McGee agreed, among other things, to ship the chemical in containers less susceptible to heat and shock, and reduce by 50 percent its supply of unfinished ammonium perchlorate.

But the company declined to agree on an across-the-board limit on ammonium perchlorate storage and also refused department requests to increase the distance between stacks of the chemical ready for shipment.

Kerr-McGee will allow a six-member team of experts to visit the plant Thursday and both Kerr-McGee and the department have informally agreed to abide by whatever the experts decide, Ms. Godwin said.

''There is still a conflict,'' Parrish said. ''There will be a meeting of the minds, and I expect a lengthy meeting. We will ask pointed questions and we expect them to give pointed answers.''

The Kerr-McGee plant is now the only plant in the country still capable of making ammonium perchlorate. Henderson is about 10 miles southeast of Las Vegas.

The cause of the Pacific blast is still under investigation. Pacific Engineering officials have said the blast may have been caused by a leaking natural gas line.