When explosions ripped apart a rocket fuel plant in Henderson, Nev., earlier this week, shock waves caused widespread damage, knocking windows out of many buildings, including Mayor Lorna Kesterson's house several miles away.

And the effects of the blast may be felt as far away as Salt Lake County on May 10 when officials from Hercules Inc., a rocket manufacturer on the west side of the county, ask planners for permission to expand so they can build Titan IV missiles.Residents from nearby Magna worried long before the Nevada accident that the new $115 million facility would increase the danger from an accidental explosion, a worry company officials claim is unfounded. The Nevada accident also may shed new light on whether a half-mile buffer around Hercules is adequate to protect nearby homes, county officials said Thursday.

"I'm amazed at the damage (in Nevada)," said Commissioner Dave Watson, who said he spent most of Thursday on the telephone talking to officials in Clark County, Nev. "There was damage to people and things all the way in Las Vegas."

Hercules officials recently threatened to move from Utah unless the county stopped developers from building within the buffer zone. The threat of an accidental explosion would cause the company's insurance rates to rise if homes were built in the area, officials said.

But now it is the county that is concerned about the threat of an explosion. The Planning Commission already has waited two months to consider the Hercules expansion, which is the first item on their agenda at the 8 a.m. meeting Tuesday. Other county officials said Thursday the decision should be delayed even further.

Watson said he wants to know more about the Nevada explosion.

"Hercules would be wise to ask us to postpone a decision," he said. "This is in our backyard. If something were to occur here it would have much more devastating effects than what Las Vegas had."

But Hercules officials say they have no plans to postpone the expansion. Jack DeMann, Hercules' public affairs director, said it is difficult to know whether there are similarities between Hercules and Pacific Engineering and Production Co. in Nevada. Hercules uses some of the products produced in Nevada, but the plants serve different functions.

"We don't know what happened down there, but we know it's a vastly different operation than ours," DeMann said.

Kesterson said Wednesday's blast knocked loose a glass panel at City Hall, located on the opposite end of Henderson. Although no one in the building was injured, ceilings collapsed in some of the offices.

Garage doors and windows were damaged in many homes throughout Henderson, Kesterson said.

"Residents really don't live that close (to the plant that exploded)," she said. "Probably all of them live more than one-half mile away."

Hercules' expansion request comes several months after local governments finalized an agreement that keeps developers out of the danger zone around the plant.

The agreement calls for West Valley City to annex half of Hercules and to buy $10 million worth of undeveloped land in the danger zone. Hercules also agreed to buy about $8 million worth of land.

The Titan IV facility will be in the unincorporated county and will make up for some of the tax money the county lost when West Valley City annexed half the plant.