National Organic Standards Board (NOSB)

Handling Subcommittee

Petitioned Material Proposal - Polyalkylene Glycol Monobutyl Ether (PGME)

February 24, 2015

Summary of Proposed Action:

Polyalkylene Glycol Monobutyl Ether (PGME) polymeric fluid is a boiler steam additive 

petitioned for use in feed pellet mills. The petition is specifically for PGME with a requested 

restriction of a minimum molecular weight of 1500, in accordance with conditions required by 

21CFR Section §173.310. The Petitioner is requesting that PGME be added to the National List

of Approved Materials at §205.605. The National Organic Standards Board (NOSB) proposes 

not to add PGME to the National List as petitioned.

Background: 

On October 9, 2012, Pellet Products, Inc. petitioned the USDA National Organic Program (NOP)

to add polyalkylene glycol monobutyl ether (PGME) to the National List of Approved Materials 

under section §205.605. Following this, PGME was first considered by the National Organic 

Standards Board (NOSB) for use as a boiler water additive at the NOSB meeting in April 2013. 

Information provided in a Technical Report (TR) requested by the NOSB Handling 

subcommittee, dated June 7, 2013, indicated that PGME does not contact food. The report 

stated that this is because PGME is non-volatile; PGME precipitates at boiler temperatures and 

is not delivered with steam, but stays in the boiler as a precipitate until the boiler cools below the 

cloud point and it may be removed during boiler blow-down.

Based on the findings of the TR, the NOSB Handling Subcommittee developed a proposal on 

August 20, 2013 stating that PGME was not required to be on the National List because PGME 

in liquid water does not come into direct contact with organic food. However, public comment for 

the fall 2013 indicated that PGME may in fact come in to contact with organic product.

In the fall 2013, following the public comment period, there was no NOSB meeting due to the

government shutdown. At the NOSB’s next meeting on April 29, 2014, PGME was further 

discussed. Following review and public comment, the NOSB Handling Subcommittee requested 

an additional Technical Report of limited scope, as well as further information and clarification 

from the Petitioner. The Petitioner provided some additional information in a letter dated 

December 3, 2014. Meanwhile, the limited scope TR was received on January 28, 2015.

As requested by the NOSB, the limited scope TR addressed the following questions: 1) What 

evidence is there that there is entrainment of PGME in water droplets during normal use?; and 

2) If used as petitioned, would PGME come into contact with the organic product (pelleted 

feed)?

Discussion:

Function of substance

PGME is added as a processing aid to water that is used to make steam for the production of 

pelleted livestock feeds. PGME functions to reduce foaming and also functions as a lubricant. 

PGME has the unique property of inverse solubility such that it dissolves easily in cold water, 

but at temperatures over 104F (cloud point) it is completely insoluble. (TR, 2013, lines 59-61) 

Thus, PGME is not delivered with the steam, but remains in the boiler as a precipitate until the 

Page 27 of 249
boiler cools below cloud point. The substance, therefore, has minimal contact with the pelleted 

feed. Precipitated PGME may also be removed during boiler blow-down (TR, 2013, lines 112-

115).

Is there entrainment of PGME in water droplets during normal use?: Yes .

In a supplemental letter dated December 3, 2014, the Petitioner states the following: “PGME is 

introduced directly into steam lines prior to entering the conditioner whereby its nature acts as a 

wetting agent and lubricant for the pellet die. Due to the introduction site and the resulting 

increase in through-put and pellet Durability Index (PDI), it is evident that PGME is entrained in 

the water during normal use. It is metered based upon the through-put of the pellet mill. Under 

21CFR Part 178 Subpart D Sec 178.3570, Certain Adjuvants and Production Aids, PGME can 

be safely used in and on machinery used for producing or processing feed. The metered 

amount of PGME is maintained at <3ppm, whereas the limit is not to exceed 10ppm.” 

However, the limited scope TR of January 28, 2015 states the following: “Thus, unlike solids 

that are dissolved in boiler water at steam-producing temperatures (e.g. sodium chloride), 

PGME is insoluble at steam production temperatures and unlikely to carryover dissolved in 

moisture entrained by steam.” (lines 89-91). The report continues, “Entrainment traps and 

filtration devices incorporated in the 3-A system standard remove particulates, including PGME 

precipitate if it is present as a result of a boiler malfunction.” (lines 107-109).

If used as petitioned, would PGME come in to contact with the organic product (pelleted 

livestock feed)? Yes.

The Petitioner states in his letter of December 3, 2014 that PGME “does come in to contact with 

the finished pelleted feed stock but well below limits set by 21 CFR....”

The limited scope TR of January 2013 provides the following: “However, steam that has 

entrained moisture may contain these solids as a result of carry over. Foaming is likely to 

enhance carryover of dissolved solids. The prevention of foaming prevents carryover. PGME 

prevents foaming eliminating one source of carryover. In addition, it is not soluble in water at 

steam-producing temperatures. Although, it does in fact come into contact with the water from 

which steam is produced, it does not evolve from the boiler into the steam as a particulate. 

PGME is not added directly to the pellet mash.” (Lines 124-129)

Adverse impacts: 

PGME polymers have a low degree of toxicity (TR 2013, line 80). Since they are generally nontoxic, PGME polymers have been approved for a variety of uses in which surfaces or water 

treated have the potential to come into contact with food. It has also been approved for a variety 

of foam control applications. In these applications only a potential exposure is assumed. (TR 

2013, lines 86-92) Additionally, because PGME polymeric fluids are water-soluble and non-toxic 

at low concentrations, they are considered environmentally friendly compounds with respect to 

petroleum-based lubricants that are not water soluble. (TR 2013, lines 148-151). See also TR 

2013 lines 494-502. There have been no reported effects of PGME on human health. (TR 2013 

lines 526-et seq).

PGME presently has a range of uses approved by the FDA. However, Canadian, CODEX and 

Japanese standards do not address this additive. EEC standards require that processed feeds 

shall not have been processed with the aid of chemically synthesized solvents (TR 2013, 301-

Page 28 of 249
302). Meanwhile, IFOAM requires all additives to be declared. PGME is not included in any 

IFOAM list, but would be considered a non-volatile water additive that is not likely to be 

entrained in steam (TR 2013, lines318-320). Finally, The FDA’s GRAS list does not address this 

material.

Manufacture:

PGME is manufactured from ethylene oxide, by chemical processes. PGME is commonly used 

in modern conditioning systems for pellet feed manufacturing, which includes the use of steam. 

In this process, steam is directly injected into the product with a tubular apparatus called a 

conditioner. This heat, plus water, pressure, and time to reach a physical state, facilitates 

compaction of the feed mash into pellets. This approach offers the manufacturer and the feeder 

various advantages which justify using additional energy for steam pelleting. Mainly, the process 

increases production capacity and positively affects the physical, nutritional, and hygienic quality 

of the produced feed. While dry pelleting is done at 40P

o

PC, the use of steam to raise 

temperatures to 65°C and 78°C results in increases in the production rate of 250% and 275%, 

respectively. Production rate increased only 9% when the conditioning temperature was raised 

from 65 to 80°C. 

Steam conditioning also decreases fixed costs such as labor and maintenance of equipment. 

For example, die and roller replacements are another major cost in pelleting. Observing the 

temperature increase of mash pressed through the pellet die and the electrical energy used to 

pellet, it can be seen that steam conditioning decreases mechanical friction. A decrease in 

friction increases both die and roller life, reducing the frequency of replacement. Thus, while the 

main contribution of steam conditioning is improved nutrition of the pellets, its contribution to 

productivity and cost-savings is also significant. (TR 2013, lines 461-474)

Natural Sources and Alternatives:

There are no natural sources of PGME. Nor are there many natural antifoam chemicals for 

boilers, in general. Castor oil is a natural compound that has been used to prevent foam in 

boilers. However, if castor oil is used care must be taken to condition boiler water so that it is 

not alkaline. In the case of alkaline boiler water, castor oil will undergo hydrolysis to form the 

sodium soap of ricinoleic acid. Although not toxic, this soap may exacerbate foaming in the 

boiler. In addition to castor oil, and depending upon the specific boiler conditions, other natural 

oils such as lard, lard burning, soybean, corn, maize, cod liver, cottonseed, olive, sunflower, 

safflower, peanut, ground nut, grape seed, linseed, poppy seed castor and palm oil may be 

used. Carnauba and peat waxes also have been used as boiler antifoams. As a note, none of 

these natural chemicals is as effective or has the performance and characteristics provided by 

PGME. Extensive water treatment is also an alternative to using antifoam chemicals. Water can 

be treated using reverse osmosis filtration or ion exchange resins to reduce dissolved solids. 

(TR 2013, lines 628-638)

In considering all of the OFPA criteria, and additional criteria at 205.600 (b), it appears that 

PGME does come into contact with the organic product and that pelleted feed can be produced 

without use of PGME.

Evaluation Criteria (see attached checklist for criteria in each category)

 Criteria Satisfied? 

 Impact on Humans and Environment ☒ Yes ☐ No 

☐ N/A 

Page 29 of 249
 Essential & Availability Criteria ☐ Yes ☒ No 

☐ N/A

 Compatibility & Consistency ☐ Yes ☒ No 

☐ N/A 

 Commercial Supply is Fragile or Potentially Unavailable ☐ Yes ☐ No 

☒ N/A 

as Organic (only for §205.606)

Substance Fails Criteria Category 2, 3

Subcommittee Action & Vote: 

Classification Motion: To classify Polyalkylene Glycol Monobutyl Ether (PGME) CAS 9038-

95-3 as synthetic

Motion by: Jean Richardson 

Seconded by: Tracy Favre 

Yes: 7 No: 0 Absent: 1 Abstain: 0 Recuse: 0 

Listing Motion: To list Polyalkylene Glycol Monobutyl Ether (PGME) CAS 9038-95-3 on 

§205.605 (b) of the National List with the annotation: with molecular weight greater than 

1500, for use as a boiler additive in pelleted feed production

Motion by: Jean Richardson 

Seconded by: Tracy Favre 

Yes:0 No: 7 Absent: 1 Abstain: 0 Recuse: 0 

Proposed Annotation: with molecular weight of 1500, for use as a boiler additive in pelleted 

feed production

Basis for annotation:  To meet criteria above ☐ Other regulatory criteria ☐ Citation 

 

Approved by Harold Austin, Subcommittee Chair, to transmit to NOSB February 24, 2015

NOSB Evaluation Criteria for Substances Added To the National List - Handling

Category 1. Adverse impacts on humans or the environment? PGME 

Question Yes No N/A Comments/Documentation. (TAP; 

petition; regulatory agency; other)

1. Are there adverse effects on the 

environment, or is there a probability of 

environmental contamination during use 

or misuse of the substance?

[§205.600(b)(2), [§6518(m)(3)]

x x PGME is manufactured from ethylene 

oxide, propylene oxide and butanol which 

are chemical products of the petroleum 

industry. Each of these chemicals is 

extremely toxic. (TR 2013, 519-520) 

Transport of PGME is unregulated. (TR 

2013, 516) 

2. Are there adverse effects on the 

environment or is there a probability of 

x See 1 above and TR 2013, 149-151

Page 30 of 249
environmental contamination during 

manufacture or disposal of the 

substance? [§6518(m)(3)]

3. Are there any adverse impacts on 

biodiversity? (§205.200)

x PGME is not readily biodegradable (TR 

2013, 504 and lines 513-520)

4. Does the substance contain inerts 

classified by EPA as ‘inerts of 

toxicological concern’? [§6517 

(c)(1)(B)(ii)]

x

5. Is there undesirable persistence or 

concentration of the material or 

breakdown products in the environment? 

[§6518(m)(2)]

x x PGME is not readily biodegradable.

6. Are there any harmful effects on human 

health from the main substance or the 

ancillary substances that may be added 

to it? [§6517(c))(1)(A)(i); 6517 

(c)(2)(A)(i); §6518(m)(4), 205.600(b)(3)] 

x There have been no reported effects of 

PGME on human health (TR 2013, 526) 

et seq)

7. Is the substance, and any ancillary 

substances, GRAS when used according 

to FDA’s good manufacturing practices? 

[§205.600(b)(5)]

GRAS does not address PGME. Title 21 

CFR 178.3570 provides that PGME 

polymeric fluids may be used as a 

lubricant with incidental food contact at a 

concentration of less than 10 parts per 

million (TR 2013, 410-412)

8. Does the substance contain residues of 

heavy metals or other contaminants in 

excess of FDA tolerances? [§205.600 

(b)(5)]

x Data was not found to substantiate the 

presence of detectable heavy metal 

contamination in PGME (TR 2013 487-

488) and TR 2013, 480-487

Category 2. Is the Substance Essential for Organic Production? PGME 

Question Yes No N/A Comments/Documentation. (TAP; 

petition; regulatory agency; other)

1. Is the substance agricultural? [§6502(1)] x

2. Is the substance formulated or 

manufactured by a chemical process? 

[§6502(21)]

x TR 2013 line 328, and lines 366-368 and 

line 374

3. Is the substance formulated or 

manufactured by a process that 

chemically changes a substance 

extracted from naturally occurring plant, 

animal, or mineral sources? 

[§6502(21)]

x See 2 above

4. Is the substance created by naturally 

occurring biological processes? 

[§6502(21)]

x See 2 above

5. Is there a natural source of the x There are no natural sources of PGME 

Page 31 of 249
substance? [§ 205.600(b)(1)] (TR 2013, 394)

6. Is there an organic substitute? 

[§205.600(b)(1)]

x Yes, there are a number of oils, such as 

sunflower , lard, soybean, corn, safflower 

etc which could be used, but very little 

data exists as to the efficacy of such oils 

for the purpose petitioned herewith(TR 

2013, 665-668)

7. Is the substance essential for handling of 

organically produced agricultural 

products? [§205.600(b)(6)]

x x Could use a mechanical piping design for 

the boiler, (TR 2013, 249-250) as 

required under Canadian standards for 

culinary steam. Can make pelleted feed 

without the use of PGME.

8. Is there a wholly natural substitute 

product?

[§6517(c)(1)(A)(ii)]

x There are a range of oils as noted in 7 

above (TR 2013, 665-668)

9. Are there any alternative substances? 

[§6518(m)(6)]

x As in 8 above

10. Is there another practice (in farming or 

handling) that would make the substance 

unnecessary? [§6518(m)(6)]

x Could try to make pellets without steam

(TR 2013, 655-664) 

Could limit livestock feed to non-pelleted 

feeds and forage.

Could use natural anti-foaming 

chemicals, but limited efficacy (TR 2013, 

629-638)

11. Have the ancillary substances associated 

with the primary substance been 

reviewed? Describe, along with any 

proposed limitations. 

Category 3. Is the substance compatible with organic handling practices? PGME 

Question Yes No N/A Comments/Documentation. (TAP; 

petition; regulatory agency; other)

1. Is the substance consistent with organic 

handling? 

[§6517(c)(1)(A)(iii); 6517(c)(2)(A)(ii)]

x

2. Is the manner of the substance’s use, 

manufacture, and disposal compatible 

with organic handling? [§205.600(b)(2)]

x Yes, Provided it is manufactured and 

used according to regulations

3. Is the substance compatible with a 

system of sustainable agriculture? 

[§6518(m)(7)]

x x

4. Are the ancillary substances reviewed 

compatible with organic handling [?

5. Is the nutritional quality of the food 

maintained with the substance? 

[§205.600(b)(3)]

x TR 2013, 463-465

Page 32 of 249
6. Is the primary use as a preservative? 

[§205.600(b)(4)]

x Although not intended as a preservative, 

PGME addition to boiler steam improves 

steam quality, which improves pellet 

hardness (TR 2013, 423)

7. Is the primary use to recreate or improve 

flavors, colors, textures, or nutritive 

values lost in processing (except when 

required by law)? [§205.600(b)(4)]

x

Category 4. Is the commercial supply of an organic agricultural substance fragile or 

potentially unavailable? [§6610, 6518, 6519, §205.2, § 205.105(d), §205.600(c)] PGME 

Question Yes No N/A Comments/Documentation. (TAP; 

petition; regulatory agency; other)

1. Is the comparative description as to why 

the non-organic form of the material 

/substance is necessary for use in 

organic handling provided? 

x

2. Does the current and historical industry 

information, research, or evidence 

provided explain how or why the material 

/substance cannot be obtained 

organically in the appropriate UformU to 

fulfill an essential function in a system of 

organic handling? 

x

3. Does the current and historical industry 

information, research, or evidence 

provided explain how or why the material 

/substance cannot be obtained 

organically in the appropriate UqualityU to 

fulfill an essential function in a system of 

organic handling? 

x

4. Does the current and historical industry 

information, research, or evidence 

provided explain how or why the material 

/substance cannot be obtained 

organically in the appropriate UquantityU to 

fulfill an essential function in a system of 

organic handling?

x

5. Does the industry information about 

unavailability include (but is not limited 

to) the following?:

a. Regions of production (including 

factors such as climate and number 

of regions);

x

Page 33 of 249
b. Number of suppliers and amount 

produced;

x

c. Current and historical supplies 

related to weather events such as 

hurricanes, floods, and droughts that 

may temporarily halt production or 

destroy crops or supplies; 

x

d. Trade-related issues such as 

evidence of hoarding, war, trade 

barriers, or civil unrest that may 

temporarily restrict supplies; or

x

e.Other issues which may present a 

challenge to a consistent supply?

x

Page 34 of 249