[USCC] Poison Oak in Compost

Thu Apr 9 21:04:53 CDT 2009

We compost poison oak fairly regularly as a small percentage of our green
waste composting operation  without any apparent ill effect.

Jeff Creque
West Marin Compost Coalition

> [Original Message]
> From: Matthew Cotton <matt at mattcotton.com>
> To: Compost Discussion List <compost at mailman.cloudnet.com>
> Date: 4/9/2009 12:18:01 PM
> Subject: Re: [USCC] Poison Oak in Compost
>
> Jack -
>
> This is an issue that comes up from time to time with compost. Bob  
> Rynk did a Q&A column on this for BioCycle back in 2000 (see below)  
> and found that the active chemical in Poison Oak/Ivy/Sumac (Urushiol)  
> is pretty hardy stuff.  No definitive fate of Urushiol in compost  
> studies that I've heard of.
>
> If you live around the stuff you know that it can and does get on  
> anything, tools, clothes, dogs, etc. It can also take days to present  
> symptoms.  I'm sure that some of this material finds it's way into  
> commercial compost piles and I imagine it is at least somewhat  
> degraded by the composting process. However, as Bob's article  
> cautions against burning, I would be very careful about composting  
> it. I wouldn't and don't compost it at home;  I know of at least one  
> reliable case of a colleague inhaling compost with poison oak in it  
> (at a farm-scale facility) and internalizing the poison resulting in  
> many unpleasant injections and time off. I also imagine that in a  
> typical commercial facility it gets diluted quite substantially with  
> other materials.
>
> Hope this is useful. I'm scratching a little already.
>
> Matthew Cotton
> Integrated Waste Management Consulting, LLC
> 19375 Lake City Road
> Nevada City, CA  95959
> (530) 265-4560
> Fax (530) 265-4547
> matt at mattcotton.com
> www.mattcotton.com
>
> A Reader's Q&A column in BioCycle (May 2000) discussed the possible  
> fate of the poison ivy toxin during composting. I have pasted the Q&A  
> text below. It seems consistent with the comments submitted so far.
>
> ************************************************************************ 
> ***
>
>
> Q. What is the fate of poison ivy in a composting system?  The owners  
> of a large pile of brush have asked to burn the pile.  They say  
> composting will not destroy the oils in the plant. Will burning pose  
> even a greater threat through airborne contamination?
>
> A. While there is a great deal of information available about the  
> poison ivy plant, and the rash that it causes, there is little  
> guidance available about how to dispose of it.  Fact sheets, books,  
> and web pages caution us not to touch poison ivy, and not to burn it,  
> but they stop short of
> recommending how to dispose of poison ivy vegetation. Burning poison  
> ivy is a bad idea (except under controlled conditions).  People have  
> developed severe reactions from breathing in smoke particles from  
> burning vines. Burying poison ivy in the ground and putting it in the  
> trash have been suggested
> as disposal methods but these alternatives have obvious  
> disadvantages, especially if poison ivy is mixed with large  
> quantities of yard trimmings. Apparently, there isnít a good method,  
> or at least a certain method of safely disposing of poison ivy.
>
>   Intuitively, some poison ivy experts and composting practitioners  
> guess that the poison ivy toxin decomposes during composting but  
> there are plenty of ìifsî and ìmaybesî in their statements. Outside  
> of the compost pile, there is ample evidence that the poison ivy  
> toxin can persist and remain potent
> for years.  Unfortunately, there isnít a clear cut answer about the  
> fate of poison ivy during composting. Here is what we do know.
>
>   The rash that occurs from poison ivy, poison oak and poison sumac  
> is caused by a family of organic compounds called urushiol  
> (pronounced oo-roo shee-ohl , or you-ROO-she-ol, depending whether  
> you read it in the north or south). Urushiol includes several organic  
> molecules with an aromatic structure,
> categorized as catechols. The literature on poison ivy also refers to  
> the toxin as an oil or oleoresin but urushiol is the more specific  
> term used to identify the oily toxin in the sap.
>
>   The urushiol-carrying sap is present in the roots, stems, leaves  
> and fruit (but not in the pollen). The roots, in particular, contain  
> high concentrations of urushiol. The sap is released when the plant  
> is damaged by bruising, cutting, mowing, scraping, wind, or insects.  
> One also can contact
> urushiol indirectly after the sap gets on clothing, shoes, tools,  
> pets, and bark and firewood previously covered with poison ivy.   
> Urushiol is not volatile but shredding, mowing, or burning the plants  
> can create airborne particles that increases the chance of exposure.  
> The plant is most potent in
> the spring and early summer when the sap is rising and the urushiol  
> content is high. The dreaded sap is less abundant in the winter but  
> still present and potent in the roots, stems, vines and twigs of the  
> plant. Therefore, if yard trimmings contain poison ivy (or poison oak  
> or sumac) residue, there
> are urushiols about.
>
>   Urushiol is a stubborn substance.  It has been shown to remain  
> potent on dead plants, clothing and contaminated objects for years  
> (bad news for everyone).  In one study, plants stored in dry  
> conditions and in submerged water for 17 months were less potent but  
> stilled caused a rash in sensitive
> individuals. However, these are not the biologically-rich conditions  
> of a compost pile.  Because urushiol is organic, it is subject to  
> biological degradation (good news for composters).  One reference  
> even suggests that under hot humid conditions, urushiol becomes inert  
> in about a week (more good
> news for composters). Unfortunately, the research basis for this  
> statement is not identified.
>
>   Still, there are other indications that urushiol decomposes  
> naturally. First, we are not overrun with cases of poison ivy despite  
> the persistence of the toxin and ubiquity of the plants. Secondly,  
> according to Susan Carol Hauser, author of Natureís Revenge1, leaves  
> that naturally fall off the plant
> do not contain urushiol. Furthermore, leaves do gradually lose  
> potency over time. Finally, there is anecdotal testimony.  For  
> instance, commenting to the U.S. Composting Council Internet  
> listserv, the manager of a large yard trimmings facility mentioned  
> that users of raw shredded yard trimmings
> mulch have reported developing the poison ivy rash while no users of  
> the composted product have.
>
>   Large-scale composting could be a rational approach for disposing  
> of poison ivy-laden yard trimmings, given the lack of good  
> alternatives and the fact that urushiol is thought to decompose under  
> conditions typical to composting. However, without more scientific  
> evidence, it remains a risky venture.
> In any case, it deserves due caution and common sense in handling the  
> raw feedstocks and the products. To adequately decompose, the  
> urushiol must be exposed. Because poison oak, sumac, and even poison  
> ivy are woody plants with fairly thick stems, the plant material  
> needs to be shredded prior to
> composting. However, shredding also releases the sap, spreading it  
> among the shredded material and possibly into the air near the  
> shredder. This raises concerns about using uncomposted mulch made  
> from the shredded yard trimmings containing poison ivy.  As a side  
> note, given the uncertainties, it is
> wise to keep poison ivy vegetation out of the backyard compost pile.
>
> 1 Additional sources of information: 1. Natureís Revenge, The Secrets  
> of Poison Ivy, Poison Oak, Poison Sumac and Their Remedies, Susan  
> Carol Hauser, Lyons & Buford Publishers; 2. Poison Ivy, Western  
> Poison Oak and Poison Sumac Agriculture and Agri-Food Canada  website:
> http://res.agr.ca/brd/poisivy.html; 3. Outsmarting Poison Ivy and Its  
> Cousins, by Isadora Stehlin, U.S. Food and Drug Administration  
> website: http://www.fda.gov/fdac/features/796_ivy.html; 4. Poison  
> Ivy, Oak & Sumac Information Center website : http:// 
> poisonivy.aesir.com/.
>
>
>
>
> On Apr 9, 2009, at 9:35 AM, Jack Hoeck wrote:
>
> > Hello Compost World
> >
> >
> >
> > Does anyone have any info on the fate of poison oak/poison ivy oils in
> > composting systems or in soil? Can it survive a 90 to 120 day compost
> > cycle?
> >
> >
> >
> > Jack Hoeck
> >
> > VP Environmental Services
> >
> > Rexius
> >
> > 1275 Bailey Hill Rd.
> >
> > Eugene, OR 97402
> >
> > 1-541-342-1835
> >
> > 1-888-473-9487
> >
> > jackh at rexius.com
> >
> >
> >
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> _______________________________________
> Join us as the US Composting Council's 18th Annual Conference & Trade
Show, January 24-27, 2010 at the Wyndham Orlando Resort, FL. The Largest
Conference & Exhibition in North America for the Composting, Wood Waste, &
Organics Recycling Industry. The Most Comprehensive Program of Training
Courses, Educational & Technical Presentations, and Facility Tours & "Live"
Equipment Demonstrations at the Disney/Reedy Creek Composting Facility.
Conference Highlights & Program, Registration forms, Exhibitor Information
and Sponsorship Opportunities available at the USCC website
www.compostingcouncil.org or call the USCC at 631.737.4931
>
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> _______________________________________
> This list is a service provided by the US Composting Council (USCC).
> (c) Copyright 2004 United States Composting Council - All rights reserved
>
> Opinions expressed do not necessarily represent the USCC, the Foundation,
or the Board of Directors.
>
> Non-members of USCC are encouraged to join the Council through its
website at: http://www.compostingcouncil.org/membership.cfm
>
> Members posting CC copies to the list and other addresses may have their
posting privileges suspended. For discussion list policies and information
regarding subscribing, unsubscribing, digest or other options, go to:
http://mailman.cloudnet.com/mailman/listinfo/compost
>
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a message to the List Manager at compostlistmanager at compostingcouncil.org