Poison » Phosphine, a colorless gas used to kill rodents, is toxic when ingested or inhaled.
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The 15-month-old sister of a Layton girl who died Saturday has been hospitalized in critical condition as investigators try to understand the role a pest-control chemical might have played in making the girls and their family sick.
Rebecca Toone, 4, died Saturday after she began having trouble breathing. The Utah Medical Examiner's Office conducted an autopsy but has not determined a cause of death, Layton police Lt. Quinn Moyes said. Toxicology tests are expected to take up to eight weeks to complete.
Rebecca Toone's parents and siblings were hospitalized with flu-like symptoms Saturday. They were all discharged Sunday, but Rebecca's 15-month-old sister, Rachel, fell ill again Sunday afternoon and was taken to Primary Children's Medical Center. She is still at the center and in critical condition Tuesday.
Investigators say the chemical, believed to be phosphine, may have wafted into the family's home after an exterminator dropped Fumitoxin aluminum phosphide pellets in burrow holes in the lawn Friday to kill voles, a small, burrowing rodent.
The pellets release a colorless gas that has a fishy or garlicky odor when they come in contact with moisture. The off-gas, phosphine, is toxic when ingested or inhaled, according to the Agency for Toxic Substances and Disease Registry, which is affiliated with the Centers for Disease Control and Prevention.
The Bountiful-based exterminating company Bug Man positioned about 1½ pounds of pellets alongside a sidewalk leading to the Toone's front porch, coming within about seven feet of the front door and three feet of the garage, according to Lt. Col. Tyler Smith, commander of the Utah National Guard's 85th civil support team, which is testing and cleaning up the potential contamination.
Inspectors believe the phosphine gas collected in an open space under the stairs to the porch and "somehow seeped into the house," Smith said.
The pellets are not to be used within 15 feet of any building occupied by people or animals, especially homes, according to a Fumitoxin use manual on the Web site of its manufacturer, Pestcon Systems, Inc.
The manual further specifies the amount of Fumitoxin recommended for rodent control: 2 to 4 tablets per opening.
At a weight of 3 grams per tablet, 1½ pounds of Fumitoxin translates to 227 tablets -- appropriate for at least 56 vole burrows.
Smith did not say how many burrow holes were reported in the front lawn. National Guard crews had dug up the affected dirt and mixed it with water to neutralize the chemical, Smith said.
Moyes said the company that applied the chemicals was licensed and certified to use it.
"With [certified pest control companies], we expect them to follow the recommendations," Layton Fire Chief Kevin Ward said. "If they don't follow the precautions, something like this can happen."
The Utah Department of Agriculture and Food sent two investigators to the scene on Monday to see whether state or federal pesticide laws might have been violated.
"We'll just go a step at a time," said Claire Allen, the director of the state Division of Plant Industry. "We'll do a detailed report of what took place."
The state investigates up to 300 pesticide cases a year -- most of them regarding certification questions -- and about 50 of those are cases in which pesticides might have been misused. But officials can only remember one other recent case where a pest-control chemical caused a death -- when a man in Cache County died after using algae killer.
"It's a tragedy," said Henry Nahalewski, who is part of the state's pesticide team. "My heart goes out to the family."
The U.S. Environmental Protection Agency, which has delegated authority over pesticide-use enforcement to the state, will eventually receive a copy of the state's report.
Peg Perrault, of EPA's pesticide team in Denver, said about nine years ago there was another case of a child dying from aluminum phosphide applied near a home. But she said it is too soon to make any judgments about the Utah case. In 1998, the EPA proposed increasing the buffer zone around homes treated by phosphine from 15 feet to 100, but the suggestion was never adopted.
People who inhale phosphine typically experience chest pain, nausea, vomiting and death, according to the CDC. Children tend to have a greater exposure than adults because they breathe more frequently and because they are closer to the ground where the vapors settle.
Noted Barbara Crouch, director of the Utah Poison Control Center: "There is no specific antidote."
Rebecca Toone's mother initially called fire crews Friday night after a carbon monoxide detector sounded at their home, near 1500 North and 2400 West. Carbon monoxide readings in the air and in one of the residents' blood were slightly elevated, but not dangerously so, said Ward. Questar Gas crews ventilated the house and investigators found no leaks in carbon monoxide sources.
On Saturday night, Rebecca's mother brought her to the Wee Care pediatric clinic near the Davis Hospital because the child was struggling to breathe, Ward said. The girl then was taken to the hospital, where she died.
The next morning, National Guard crews detected phosphine concentrations of 30 parts per million in the garage, near the entryway and in a bedroom, Smith said.
Concentrations of 50 parts per million can be life-threatening for a 150-pound adult, Smith said.
Investigators do not know whether the bedroom was used by Rebecca or Rachel, but Smith noted it was furnished with bunk beds, suggesting it's a child's room. Crews are investigating whether that gas may have triggered the carbon monoxide detector.
In a statement, the Toone family wrote: "We are greatly saddened by the passing of our 4-year-old daughter Rebecca Toone. Our 15-month-old daughter Rachel is being treated at Primary Children's hospital with serious complications related to symptoms similar to Rebecca's. We love these girls and our two older children with all our hearts.
"We have been sustained by the love of our family, friends and neighbors, and by our faith and understanding of our purpose in this life and the world to come."
The family is accepting donations through a fund in Rebecca Toone's name at Wells Fargo bank branches.
The Toones have been staying with family or friends, Moyes said, until authorities determine they can safely return to their home.
No neighbors near the Toones have reported any similar symptoms, Ward said. There are no other houses evacuated in the neighborhood, he said.
Aluminum phosphide is normally applied in areas that have a heavy rat population, but it is not used by all pest-control companies, said Pete Morgan, the West Valley City branch manager of the national pest control company Orkin.
"It's something we do not use and haven't found necessary," Morgan said.
Morgan said Orkin, which was not involved in the Layton extermination, follows the Integrated Pest Management model. Under that system, pesticides are used only when necessary and exterminators apply the smallest amount needed of a pesticide that carries the least possible harm to people and the environment.
To get rid of voles, his exterminators use traps or non-airborne poisons dropped into their burrows, he said, adding, "We've never had issues with anybody feeling sick."
Greg Baumann, vice president and senior scientist for the National Pest Management Association, said voles are vegetarian rodents found in both agricultural and non-agricultural areas. They also are called meadow mice or field mice and "do raise a real challenge with control," he said.
Fumitoxin is one of the products that can be used by a exterminator with the proper license and certification to combat voles, according to Bauman. He said the label instructions say the chemical must be applied at least 15 feet from an occupied structure.
Judy Fahys and Pamela Manson contributed to this report.
Consumers who plan to use an exterminator can ask to see the chemical label information, which can be very detailed with information about health risks, proper application and emergency information. Another option is to contact your local agricultural extension office for information about integrated pest management, which relies less on chemicals.
More information is available in several languages online through the National Pesticide Information Center: npic.orst.edu/