UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D
.C

. 20460 

### MAY 

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OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

### MEMORANDUM
SUBJECT: FROM:

THRU:

TO: BEAD Chemical Profile for Registration Review: Propylene oxide (042501) Leonard Yourman, PlantPathologist

## ./)**~** Biological Analysis Branch 

## fJ

# f SepehrHaddad, Environmental Protection Specialist /;;.__, 

# f/ ' 1 • Science Information and Analysis Branch 

## 7

# ~~ JohnFaulkner, Economist 

# Q _.), /111

# ~ Economic Analysis Branch 

# r· v , t Biological and Economic Analysis Division (7503P) AmetJones, Chief

# ~ Biological Analysis**B~~ch** . 

# u
Diann Sims, Chief

# ~ Science Information and Analysis Branch Timothy Kiely, Chief

# ~**~** Economic Analysis BrancH 

# #. Biological and Economic Ana ys s Division ( P) AndreaMojica, Chemical Review Manager Risk Management and Implementation Branch4 Pesticide Re-evaluation Division (7508P)
ProductReview Panel: May 9, 2012


### INTRODUCTION The purpose ofthis document is to convey usage information and a broad overview ofthe pest managementroles ofpesticides that are beginning to undergo registration review. The anticipated audience consists ofthe team ofEPA staffcurrently evaluating the registration status ofpropylene oxide (PPO), and eventuallythe general public. This document builds uponthedata already provided in the "Usage and Label Use DataPackages" that are also provided to Registration Reviewteams by BEAD. The document is based oninformation and data available to BEAD as ofApril, 2012. PPO is a fumigant, an epoxide compound that exists at room temperature as a volatile colorless liquid (NTP, 2011). It is soluble in water and ethanol and miscible with acetone, benzene, carbon tetrachloride, methanol, and ether. PPO is very flammable, but it is stable undernormal storage conditions. Itis very reactive, particularly with chlorine, ammonia, strong oxidants, and acids. Itmay polymerize explosively whenheated or involved in a fire. PPO has beenused in chambers for the sterilization ofpackaged foods and as a postharvest treatment. Itis used as anherbicide, microbicide, insecticide, fungicide, and miticide. PPO is used primarily as a chemical intermediate inthe production ofother compounds (NTP, 2011). PPO is used to produce industrial polyurethane polyols, propylene glycols, glycol ethers, di- and tri-propylene glycols, and miscellaneous compounds. Polyurethane polyols are used to make polyurethane foams, and propylene glycols are used primarily to make unsaturated polyester resins for the textile and construction industries. PPO is also used in the preparation of lubricants, surfactants, and oil emulsifiers.
COMMON FORMULATIONS AND APPLICATION METHODS PPO is formulated as a pressurized gas. Itis used in vacuum chambers at full strength (100%) for nuts, spices, cocoa (cacao) bean, cocoapowder, and cosmetics. According to the label, it must be used at a concentration of8% with aninert gas (carbon dioxide, nitrogen) for figs, dried plums (prunes), and raisins.
USE SITES Agricultural Use Sites PPO is registered for use onthe following agricultural commodities: processed food/feed stored products (raisins, grapes, plums, prunes/figs, cocoabeans, cocoapowder, spices, birdseed, processed nuts). Non-Agricultural Use Sites PPO is registered for use onthe following non-agricultural sites: transportation vehicles, empty containers (processed feed/food, raw agricultural commodities feed/food), airtight chambers, shipping commercial transportation (containers, empty trailers, empty railroad boxcars feed/food), pharmaceutical materials, tents, and vaults.

2USAGE The Department ofPesticide Regulation (CDPR) reported that in 2010, a total of300,000 lb of PPO was used for crops in California, the 57th most used pesticide (by pound) (CDPR, 2011). There were no usage data available for PPO from other BEAD data sources, such as private market research proprietary data or USDA-NASS. A Re-registration Eligibility Decision (RED) document for this chemical was issued in 2006. According to information in the RED an estimated 64.8 millionpounds ofcommodities were treated with PPO annually. The RED also stated that PPO was used mostly onnutmeats (approximately 1.8% commoditytreated) and spices (approximately 1% commodity treated) and that EPA has established tolerance limits for PPO based onresidues from fumigation ofcocoabeans, nutmeats, herbs and spices, and some fruits (e.g., figs, prunes, and raisins) (EPA, 2006a).
HISTORY OF BEAD ASSESSMENTS FQRPROPYLENE OXIDE BEAD assessed the impact ofPPO and alternatives onalmonds, pecans, walnuts, and spices (EPA, 2006d) and responded to public comments (EPA, 2006b). Almonds. PPO has been used as a fumigant for raw almonds to reduce microbial contamination on raw almonds. A potential alternative to PPO for raw almonds are various methods ofsteam heatthat can reduce the microbial populations while maintaining the character ofraw almonds. Operating costs ofsteam systems are likely to be at least comparable to PPO for treating large lots ofalmonds; however, there is uncertainty to the ease ofdeployment and use ofsteam pasteurizationtechnology in the almond production system, especially for smaller almond handlers. IfPPO or steam systems were not available for treating raw almonds, impacts might include increased incidence ofSalmonella contamination onmarketed raw almonds (including increased costs associated with recalls) and losses associated with lots thattest positive for contamination with Salmonella or other microbes unacceptable to customers. Pecans and Walnuts. PPO treatment ofshelled pecans and walnuts is important for the portion marketed for use as ingredients in dairy and bakeryproducts. Available information suggests that there are limited alternatives (e.g. heat treatments) to PPO for treating pecans and walnuts for this purpose. IfPPO is no longer available in pecanproduction, the impact onthe pecan and walnut producers and industries that use pecans may be high. Spices. PPO is registered for use on spices to reduce insect, bacterial and mold infestations. It has a small use on spices (approximately 1% ofspices used in the U.S.), mostly for insect management. Itis not consideredbythe industry as effective inreducing high microbial populations. PPO has been banned throughout the European Union. Alternatives, depending on the particular spice being treated, include improved management and agricultural practices, product selection, heat treatments, and irradiation. Based on lowuse patterns and the availability ofalternatives that have been effective in other countries, BEAD anticipates that the spice industry would experience only minor impacts ifPPO was unavailable for

- use on spices. Similar conclusions were made in a BEAD alternatives assessment (EPA 2006c).
3BIOLOGICAL ASPECTS RELEVANT TO PROPYLENE OXIDE After outbreaks ofSalmonella, in 2001 and 2004, that were traced to raw almonds there has been an ongoing effort by the almond processing industry to avoid future incidences ofcontaminated almonds. The almond industry considers PPO an important treatment to that end (ABC, 2012). Most almonds are oil roasted, dry roasted or blanched and do not require additional treatment. A small portion ofthe nearly 2 billionpounds produced annually is currently marketed as "raw'' and the Almond Board ofCalifornia (ABC) requires surface treatment with PPO or other pasteurizationtreatments for ensuring the safety ofthese almonds (Federal Register, 2007). PPO treatment ofraw almonds both maintains the "raw" characteristics andreduces populations ofthe Salmonella pathogen. Steampasteurization is also a surface treatment and is used primarily for organic almonds (ABC, 2012). Specialized steam equipmentreduces any "cooked" effect on raw almonds. Similarto its use on almonds, PPO is also considered importantby walnut and pecanprocessors to reduce the microbial and insectpopulations in harvested pecans, especially when the nuts will be included as an ingredient in dairy orbakery items. PPO pasteurization ofshelledpecans or walnuts is important to preserve nut quality for enduse products, such as ice cream and bakery goods. Available information suggests that there are limited alternatives to PPO for this purpose. PPO may have an increasedrole as an alternative to some previous uses ofmethyl bromide, but according to the U.S. Nomination for critical use exemption ofmethyl bromide, "U.S. EPA has established tolerances for propylene oxide onprunes, figs, and raisins, but no comparative efficacy datafor commodity fumigation seems to be currently available" (UNEP, 2011).
INFORMATION THAT MAY BE USEFUL FORBEAD'S FUTURE WORK ON PROPYLENE OXIDE The various nut industries have indicated that PPO is importantto public health to reduce incidences ofSalmonella or otherpathogens for rawnut consumption. Information on advanced alternatives to PPO (e.g., heat treatment facilities) is limited and may be helpful inthe future for any further assessments required by BEAD.
REFERENCES ABC (Almond Board ofCalifornia). 2012. The Food Safety Program and Almond Pasteurization. http://www.almondboard.com/Handlers/FoodQualitySafety/Pasteurization/Pages/Default.aspx CDPR (California Department ofPesticide Regulation). 2011. The top 100 pesticides usedpounds ofactive ingredients statewide in 2010 (all sites combined). http://www.cdpr.ca.gov/docs/pur/pur10rep/top 100 ais lbslO.pdf
4EPA. 2006a. Reregistration Eligibility Decision for Propylene Oxide, July 2006 http:/ /www.epa.govIoppsrrd1 /reregistration/propylene oxide/ EPA. 2006b. BEAD Response to Phase 3 Public Comments Concerning the Reregistration of Propylene Oxide (PPO) for Uses on Almonds, Pecans, and Walnuts EPA. 2006c. Propylene Oxide (PPO) Alternatives Assessment for Use on Spices to Reduce Bacterial and Mold Contamination. EPA. 2006d. Impact Assessment ofPropylene Oxide and Alternatives on Almonds, Pecans, Walnuts and Spices (DP# 316567) Federal Register. 2007. Almond grown in California; Outgoing Quality Control Requirement. Final Rule. Agricultural Marketing Service, USDA. 7CFRPart 981. Docket: FV06-981-1FR. http://www.almondboard.com/Handlers/Documents/Outgoing-Quality-Control-Rule.pdf NTP (National Toxicology Program). 2011. Propylene Oxide. Report on Carcinogens, Twelfth Edition (2011). Pp 367-368. U.S. Department ofHealth and Human Services. http://ntp.niehs.nih.gov/ntp/roc/twelfth/profiles/PropyleneOxide.pdf UNEP (UnitedNations Environment Programme). 2011. Summary: Nomination for Critical Use Exemptions for Methyl Bromide Submitted by the United States ofAmerica onFebruary 4, 2011. http://ozone.unep.org/Exemption Information/Critical use nominations for methyl bromide/M eBr Submissions/USA-CUN-Dec%20Ex1-4-para7-201l.pdf

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