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Dr. Jayne Morrow
White Powder

Case Study Case Study Thumbnail View

Lori Miller, PE
Decontamination of Diseased Animal Carcasses


My name is Lori Miller, and I'm a professional engineer licensed in Maryland.  I work for the U.S. Department of Agriculture, the Animal and Plant Health Inspection Service, or APHIS.  APHIS is the lead federal agency when responding to an animal disease outbreak.  I serve as an environmental engineer senior staff officer, and primarily I work on the part of the response that involves decontamination and disposal of materials that would be potentially affected from the outbreak, and doing that in a way that is protective of human health and the environment.

When there's an animal disease outbreak, typically a quarantine is put around the infected area and then the animals inside the quarantine zone are destroyed and disposed of by burning or burial.  And as you may imagine, the production practices have changed a lot in the last 100 years.  So for the U.S., we haven't had an outbreak of a significant animal disease like foot-and-mouth disease since the 1920's.

The United Kingdom had an FMD outbreak in 2001, and the first thing they did was try burning the animals.  And the result was huge clouds of smoke that hung over communities for weeks at a time.  And they had to evacuate whole villages.  So they shifted their strategy away from the burning and tried unlined burial, and they took the animals to central locations where they buried them in big pits.  And then they discovered that they were contaminating the ground water, which would potentially be drinking water for people.

The U.K. looked at five different methods for disposal.  They looked at rendering, which is a process where the meat is ground up, then heated to drive off the water portion which is about 60% of the material.  They also looked at fixed incineration plants where the incinerators have emission control devices on them.  They looked at permitted landfills, which would be lined and have a liquid collection system.  And they also looked at open burning and unlined burial, and they evaluated those five options on how much risk did they pose to humans.  They found that rendering was the safest alternative, followed by fixed incineration and a permitted landfill.  Open burning was not as safe, and by far, the worse alternative was unlined burial.

In 2010, Japan had an FMD outbreak also, and they also used the same strategy and tried to bury the animals.  But what they found was that they didn't have enough burial sites so they had to stop euthanizing the animals long enough so they could find more burial sites.  And they used vaccination to prevent the spread of the disease while they were looking for the burial sites, and then once they had the sites they would go back and slaughter the animals and dispose of them.

Another example was in 2011 with South Korea.  They had an FMD outbreak. They were deploying the same strategy and unfortunately weather conditions were terrible when the outbreak occurred, and they had approximately 4,200 burial sites around the country and at least a third of them failed.  There were reports of people turning on their faucets and contaminated water was coming out from the burial sites, and at this point they have a massive groundwater monitoring program underway.

If the U.S. was to use the strategy of destroying the animals and then disposing of them by burning or burial, at even a single feed lot, the task would be overwhelming.  You would require approximately 1,700 truckloads just to get those animals from the pens to a burial pit, even if it was onsite.  And if you dug a trench for the animals and laid them end to end, that trench would have to be 151 miles long.  So let's just say that we wanted to use this strategy on a single feed lot near Amarillo, Texas.  100,000 cows at 1,000 pounds each is 100,000,000 pounds, or 50,000 tons, so you can see that applying that strategy to even a single feed lot in the U.S. would be overwhelming in its magnitude.  Thankfully the U.S. and some of our other international partners are looking at revising this strategy and finding other ways to address a foot-and-mouth or other outbreak without having such enormous environmental consequences.

So for example, using vaccinations so that the animals don't get the disease, or finding ways to minimize the number of animals that have to be destroyed if there is an outbreak to ensure protection of the environment.  If there's a feed lot in Amarillo, Texas but the nearest disposal facility is maybe just over the state border in Oklahoma, if we have a permit system in place ahead of time that spells out how the vehicle has to be loaded, sealed, and disinfected before it leaves the site, how it's labeled as it travels down the road, and how it's received in the other state; if those standards are in place ahead of time and agreed upon, then we remove the whole fear factor during the emergency.  The key aspects of this part of the response are transportation and disposal.

Clear standards, in advance of the emergency, that spell out the conditions for transporting the animals interstate or intercounty on public roads, as well as having standards for how the materials are disposed of so that they don't contaminate the environment, are very important.  With what we know today, we can already develop standards just based on best practices for disinfecting vehicles, for containing the biomass securely before it leaves the site, for having permit systems to allow the material to travel down the road and to go across state lines or county lines.  We have enough information to get those standards in place today, and thankfully there are people who are working on that right now.

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