LAS VEGAS (AP) — Las Vegas officials insist they followed federal guidance when they quarantined more than a thousand middle school students overnight over the discovery of several drops of mercury, but the U.S. Environmental Protection Agency said Friday that no such standards exist.
EPA workers help during spills of the neurotoxin, a fairly frequent occurrence at schools, but there is no set response that the agency enforces, spokesman Rusty Harris-Bishop said.
"We do not have a protocol on quarantine for mercury spills. We don't have that authority," he said.
Five to 10 drops of the element were found Wednesday at Walter Johnson Junior High School, leading authorities to keep 1,200 students and others for up to 17 hours to screen them for exposure. No illnesses were reported, but at least 50 children were contaminated. Everyone was eventually cleared of mercury residue.
Harris-Bishop said the Clark County School District made the decision about the response, which some parents criticized as over the top as they waited outside for hours for word on their children.
"We're not the responding authority here. We're brought in as a technical assist. We're not in charge. We're here to provide expertise," Harris-Bishop said.
Local officials maintain that the response aimed to ensure no students went home contaminated. High levels of exposure can cause mercury poisoning, which has symptoms including muscle weakness and speech, hearing and walking impairment, the EPA's website says.
There was no way to know the severity or reach of the contamination without the full-blown screening process, school officials say.
"We go by the recommendations by the EPA because they're the professionals in this situation," said Melinda Malone, a school district spokeswoman.
It was the largest decontamination effort the district and fire department has handled, officials said.
Mercury is a naturally occurring element and it's very likely traces already exist in schools, particularly in old science labs, said Dr. Fermin Leguen of the Southern Nevada Health District.
Even the small amount of mercury found in the school gym is considered low-level exposure and generally won't cause any lasting health effects, he said. Such quantities can be dangerous if it vaporizes, but it would not be life-threatening.
The response stirred anger in many parents, who said they did not get enough information and that the screenings took too long for the amount of mercury that spilled. It roughly equaled what can be found in an old thermometer.
Hundreds of anxious parents staked out the school, waiting as their children slowly trickled out until 5 a.m. Thursday. Students were quarantined in their classrooms until they were screened, which took about five minutes per person. They received food and water.
Kathleen Wardeh said her son Joseph was allowed to leave school at 3 a.m. Thursday. She called the process unnecessary and alarming and said she has lost confidence in the school's ability to handle a crisis.
"God forbid this was a really serious situation. How would they have handled it?" she asked. "They obviously are not prepared to handle any kind of crisis. I don't feel like my kid is safe in the public school."
The level of exposure among the contaminated students was minimal because no one is believed to have ingested it, Clark County School District police Capt. Ken Young has said.
A teacher initially reported the substance after seeing a group of boys and girls playing with it during a school assembly. The fire department confirmed the silvery liquid was mercury.
Officials were investigating reports from parents who said their children played with the substance at the school as far back as a week ago. They are also looking into whether a student brought it school.
The EPA said its testing so far confirms that the mercury was on campus before Wednesday's initial discovery.
The school is expected to reopen Monday.
Associated Press writer Alina Hartounian contributed to this story.
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