Max, a 2-year-old German shepherd, had become a regular companion on these west desert excavating trips. Aguiar often worked alone, and having the big, intimidating canine alongside made her made her feel more secure.
But this time Max wasn't there. And Aguiar quickly grew anxious, because, she says, "he never leaves my side out there."
Unease soon gave way to panic. Aguiar spent the next 15 minutes frantically screaming for Max and racing around the area. After 15 agonizing minutes, she finally found her dog, lying about 100 feet from the quarry and 15 feet from the road.
Max was dead. And a pink, foamy substance was emanating from his mouth and nostrils.
Aguiar didn't know it at the time, but her dog had been killed in a matter of seconds after yanking at, then setting off a meat-scented cyanide bomb, known as an M-44. Laid by the U.S. Department of Agriculture as part of its predator control program throughout the West, the trap's intended target was coyotes, which had been killing and harassing sheep grazing public lands in the area.
It is not the first time a family pet has instead been victimized by the device. While not an epidemic, enough dogs have been killed by M-44s in recent years to spark a backlash among environmentalists and dog owners, who call the devices indiscriminate and dangerous - not only to pets, but small children.
"They're like land mines waiting to go off," says Brooks Fahy, executive director of the Oregon-based environmental group Predator Defense. "And this isn't just happening in Oregon and Utah. It's happening all over the place. And every time, I hear the same thing. The owners have never heard of these devices. I believe hundreds, if not thousands of dogs have been and continue to be killed by these things."
Federal Agriculture Department officials acknowledge that the trap which killed Max was likely theirs, set some weeks earlier at the request of a rancher. They call it an "unfortunate," but "rare" event.
"I'm genuinely sorry this happened. I really am. This is the thing we work very hard to avoid," says Michael Bodenchuk, the department's wildlife services director for Utah.
But Aguiar and her husband Tony, who own a rock wholesale business in Fillmore, have been less than satisfied with USDA's response. They want to know why no cyanide warning signs were posted, as required by federal law, both at road intersections near the area where the traps had been set and within 25 feet of the actual traps themselves.
"I've been going out there for over 20 years," Tony Aguiar says. "I've never seen any kind of sign out there."
To Fahy, the Aguiars' story is familiar. Just a month before Max's death, he says, another Utahn watched his Labrador retriever die at the hands of an M-44 while hunting rabbits on public lands. Samuel Pollock told KUTV he did see a USDA warning sign posted on an entry road, but insists there was no warning sign near the trap itself.
Fahy also believes that what he calls a series of poisoning incidents is more than a coincidence.
The controversy and unpopularity of M-44s outside the ranching community has led the agency, he says, to soft-pedal their presence. Again and again, Fahy says he has encountered either no warning signs or signs posted in inconspicuous places when investigating a cyanide-related pet death.
"When they post the signs, they know people will be concerned, and in a lot of cases pissed off," he says. "So why raise the ire of the public if you can get away with it?"
Bodenchuk, the USDA wildlife services director, calls such assertions absurd.
"We try real hard not to let these things happen," he says. "We don't set them anywhere near where exposure to kids or pets are likely. And we review it constantly. There are places where we've had M-44s for years, where we don't anymore. Places like the Uinta Basin, which used to be a safe place but is now changing with new oil wells and roads. We may now also have to consider exposure around the [Millard County] quarry as likely, after this. We may not be able to use the device there in the future."
Bodenchuk and his higher-ups at the USDA also are adamant about another thing: Warning signs were properly posted and procedures were followed in the west desert in April.
"We put up the signs," he says. "We can't make people read them."
But Aguiar and her husband say that if signs had been in place, their dog likely would still be alive and they wouldn't be making a stink about it.
"I didn't see signs the day it happened, or the day before or the day after," Sharyn Aguiar says. "I guess I'm blind or stupid."
The couple and their son went back out to the quarry nine days after Max's death to videotape and photograph the scene. That day, they found a small piece of red paper, sporting cyanide warnings, pinned under some sagebrush. Nearby was a dead coyote.
Bodenchuk says it was a warning sign, which was probably left behind after traps and other signs were pulled shortly after Max was killed - but before the Aguiars discovered it was an M-44 that killed him and USDA was informed of the incident.
The Aguiars, who wound up filing a tort claim with USDA for $1,500 in damages, remain unconvinced.
Nobody, Sharyn Aguiar says, challenged their version of events until weeks later, when she received letters from the agency's Minneapolis office seeking proof of Max's breed, and insisting USDA procedures has been followed at the quarry.
"Typical government stuff - brush it under the rug," says Tony Aguiar. "Their problem now is, this woman is going to keep at this. But she's not after the money. She just wants to know its going to be safe the next time she goes out to the quarry with a dog."
Actually, for Sharyn Aguiar, it now goes beyond that.
"At first I just wanted to go out and post a sign that says 'Watch your dog on public land,' " she says. "Now, I want more than a sign. I want this stuff banned."