EPA REGISTRATION DIVISION COMPANY NOTICE OF FILING FOR 

PESTICIDE PETITIONS PUBLISHED IN THE FEDERAL REGISTER 

Summary of Petition 

EPA has received a pesticide petition ([insert petition number]) from Productos Químicos 

y Alimenticios OSKU S.A. (OSKU), 5212 El Guanaco, Huechuraba, Santiago, Chile

proposing, pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act 

(FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR part 180 by establishing a tolerance for 

residues of sulfur dioxide (from sodium metabisulfite) in or on the raw agricultural 

commodity blueberries at 10 parts per million (ppm). Adorno & Yoss, LLP of Washington, 

D.C. serves as the agent for OSKU. EPA has determined that the petition contains data or 

information regarding the elements set forth in section 408 (d)(2) of FDDCA; however, 

EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the 

data supports granting of the petition. Additional data may be needed before EPA rules on 

the petition. 

A. Residue Chemistry

1. Plant metabolism.

 

Residues studies (OPPTS 860.1300) were conducted in postharvest blueberries in order to 

characterize the fate of sulfur dioxide in the fruit. The residue of concern is sulfur dioxide 

released from sodium metabisulfite which is contained in pads as a sole active ingredient. 

The active ingredient sodium metabisulfite in the pads releases sulfur dioxide when it absorbs 

moisture generated by blueberries. Sulfur dioxide generating pads have been registered for 

use on post-harvest table grapes as a fungicide. The metabolism of sulfur dioxide is well 

known in the literature. (See Reregistration Eligibility Decision (RED) – Inorganic Sulfites, 

May 2007, which is available at the following EPA web site: 

http://www.epa.gov/oppsrrd1/REDs/inorganicsulfites.pdf.) 

2. Analytical method. 

An adequate residue analytical method is available for enforcement purposes. The modified 

Monier-Williams method, which is the official method of analysis approved by the 

Association of Official Analytical Chemists (AOAC), is listed in 40 CFR Appendix B to Part 

425.

3. Magnitude of residues. 

The residue studies were performed in the United States under laboratory and commercial 

conditions in order to determine the magnitude of the residue in blueberries. 

B. Toxicological Profile
Sulfiting agents have been used for centuries in food processing as sanitizing agents, 

preservatives, inhibitors of undesirable microorganisms in fermentation, inhibitors of 

browning and discoloration during the preparation, storage, and distribution of many foods, 

and in other uses. Sulfiting agents, including sulfur dioxide (SO2) and SO2 generating 

sodium metabisulfite, are listed as the Generally Recognized As Safe (GRAS) status by the 

Food and Drug Administration (FDA), with limitations, as food preservatives, while the 

pesticidal use of sulfating agents on grapes falls under EPA’s jurisdiction. EPA established a 

tolerance limit of 10 ppm for sulfur dioxide. 40 CFR 180.444. Under section 408(q) of the 

Federal Food, Drug, and Cosmetic Act (FFDCA), EPA reassessed this tolerance in May 

2007. Sufficient data were available to support the reassessment of the tolerance. An 

assessment of the toxic effects caused by sulfur dioxide is discussed in the Reregistration 

Eligibility Decision (RED) – Inorganic Sulfites, EPA, May 2007, which is available at the 

following EPA web site: http://www.epa.gov/oppsrrd1/REDs/inorganicsulfites.pdf. 

1. Animal metabolism.

The metabolism of sulfur dioxide in mammals is adequately understood. (See Toxicological 

Profile for Sulfur Dioxide, U.S. Department of Health and Human Service, December 1998, 

which is available at the following web site: http://www.atsdr.cdc.gov/toxprofiles/tp116.pdf.) 

 

2. Metabolite toxicology. 

The metabolism of sulfur dioxide is adequately known. (See Toxicological Profile for 

Sulfur Dioxide, U.S. Department of Health and Human Service, December 1998, which is 

available at the following web site: http://www.atsdr.cdc.gov/toxprofiles/tp116.pdf.)

3. Endocrine disruption. 

Reproductive effects were not observed in rats exposed to 5-30 ppm sulfur dioxide for a 

period from 9 days prior to mating until 12-14 days of pregnancy; or in mice exposed to 25 

ppm sulfur dioxide 7 hours/day on gestation days 6-15; or in rabbits exposed to 70 ppm 

sulfur dioxide 7 hours/day on gestation days 6-18. (See Toxicological Profile for Sulfur 

Dioxide, U.S. Department of Health and Human Service, December 1998, which is 

available at the following web site: http://www.atsdr.cdc.gov/toxprofiles/tp116.pdf.) 

 

C. Aggregate Exposure

Based on the use pattern of sulfur dioxide and sodium metabisulfite, EPA has determined that 

aggregate exposure to sulfites does not pose a risk concern. (See Reregistration Eligibility 

Decision (RED) – Inorganic Sulfites, EPA, May 2007, which is available at the following 

EPA web site: http://www.epa.gov/oppsrrd1/REDs/inorganicsulfites.pdf.) 

1. Dietary exposure. 

i. Food. 
Sulfur dioxide (21 CFR 182.3862) and sodium metabisulfite (21 CFR 182.3766) are listed as 

GRAS by the FDA, with limitations, as food preservatives. Sulfiting agents are found in 

many foods, primarily as a result of the GRAS preservative use. It is estimated the sulfite 

concentrations of >100 ppm may be found in dried fruits (excluding dark raisins and 

prunes), lemon and lime juices, wine, molasses and sauerkraut juice. Dried potatoes, grape 

juice, wine vinegar, gravies, fruit topping, and maraschino cherries may contain between 50 

and 100 ppm sulfur dioxide. Foods containing between 10 ppm and 50 ppm include pectin, 

fresh shrimp, corn syrup, sauerkraut, pickled foods, corn starch, hominy, frozen potatoes, 

maple syrup, imported jams and jellies and fresh mushrooms. 

The World Health Organization (WHO) has emphasized the use of appropriate labeling for 

alerting individuals who cannot tolerate sulfites. After receiving and reviewing reports of 

adverse reactions in certain individuals following ingestion of sulfating agents used as 

preservatives in food products, beverages, and fresh fruits and vegetables, the FDA required 

ingredient labels to list sulfite concentrations in excess of 10 ppm. 

The uses of products containing inorganic sulfites are limited to use as indoor fumigants and 

as fungicidal control agents on grapes. A tolerance limit of 10 ppm (expressed as sulfite) for 

sulfur dioxide is established in 40 CFR 180.444, and sufficient date are available to support 

the reassessment of this tolerance. This 10 ppm tolerance is relatively low compared to 

concentrations of sulfites in many common foods and viewed as GRAS by FDA. Further 

this level for which FDA requires labeling to alert sulfite-sensitive individuals. Therefore, 

residues resulting from the postharvest use of sulfur dioxide and sodium metabisulfite on 

grapes are not expected to be at a level of concern for the general population or any 

population subgroups. OSKU believes the proposed 10 ppm tolerance for sulfur dioxide on 

blueberries would not constitute a level of concern for the general population or any 

population subgroups. 

ii. Drinking water. 

Based on the use pattern and fate characteristics of these chemicals, EPA has concluded that 

it does not have any drinking water concerns for sulfur dioxide and sodium metabisulfite. 

(See Reregistration Eligibility Decision (RED) – Inorganic Sulfites, EPA, May 2007, which 

is available at the following EPA web site: 

http://www.epa.gov/oppsrrd1/REDs/inorganicsulfites.pdf.) 

2. Non-dietary exposure. 

Since sulfur dioxide is primarily present in gaseous form, the general public is exposed to it 

mostly by inhaling contaminated air. Exposures would be expected to be highest near 

industrial activities that involve fuel combustion. Occupational exposures to sulfur dioxide 

are associated with workers in steel processing, refinery, and chemical plants. It has been 

estimated that approximately 600,000 American workers may be occupationally exposed to 

sulfur dioxide. Some of the highest exposures occur when it is a by-product, as in the metal 

smelting industry, and in the processing or combustion of high-sulfur coal 
or oil. (See HSDB 1998, Hazardous Substances Data Bank, National Library of 

Medicine, National Toxicology Information Program, February 1998.) 

Levels of occupational exposure vary from industry to industry. Sulfite pulp worker exposure 

fluctuates but reaches levels greater than 10 ppm (26 mg/m3) in the 1950 ́s (studies in 

Finland, Norway, and the United States). (See IARC. 1992. IARC monographs on the 

evaluation of the carcinogenic risk of chemicals to man: Occupational exposures to mists and 

vapours from strong inorganic acids, and other industrial chemicals. Vol. 54. Lyon, France: 

World Health Organization, International Agency for Research on Cancer.) Because of 

modernization of facilities and processes, these levels have been falling. Roasting of ores and 

the combustion of sulfur-containing fuels in the metal industries have resulted in workplace 

exposure concentration means of 1-10 ppm (2.6-26 mg/m3) in copper smelters and 1 ppm 

(2.6 mg/m3) or less in other operations. Occupational exposure levels with a mean >1 ppm 

(2.6 mg/m3) have been measured during sulfuric acid and superphosphate fertilizer 

manufacture as well as during firefighting.

No information was found regarding the number of people potentially exposed in the 

vicinity of hazardous waste sites. However, since sulfur dioxide has been found near 

hazardous waste sites, people living near them may be exposed to higher than 

background levels. 

D. Cumulative Effects

Section 408 (b)(2)(D)(v) of the FFDCA requires that, when considering whether to establish, 

modify, or revoke a tolerance, the Agency consider “available information” concerning the 

cumulative effects of a particular pesticide residues and “other substances that have a 

common mechanism of toxicity”. EPA does not have, at this time, available data to 

determine whether inorganic sulfites, including sulfur dioxide, have a common mechanism of 

toxicity with other substances. Unlike other pesticides for which EPA has followed a 

cumulative risk approach based on a common mechanism of toxicity, EPA has not made a 

common mechanism of toxicity finding as to inorganic sulfites, including sulfur dioxide, and 

any other substances, and inorganic sulfites do not appear to produce a toxic metabolite 

produced by other substances. 

E. Safety Determination

1. U.S. population. 

EPA has determined that taking into consideration of all available information on sulfur 

dioxide and sodium metabisulfite, including the specific use pattern and limited exposure 

potential, FDA’s classification of GRAS, as well as the historical presence of sodium 

metabisulfite in cosmetics and hair care products, the use of sulfur dioxide and sodium 

metabisulfite on postharvest grapes is unlikely to pose a significant risk to the general 
population or any population subgroup. (See Reregistration Eligibility Decision (RED) –

Inorganic Sulfites, EPA, May 2007, which is available at the following EPA web site: 

http://www.epa.gov/oppsrrd1/REDs/inorganicsulfites.pdf .) OSKU believes that the use of sulfur dioxide and sodium metabisulfite on postharvest 

blueberries would not pose a significant risk to the general population. 

2. Infants and children. 

There is sufficient toxicological information for sulfur dioxide and sodium metabisulfite to 

address FQPA considerations. The available information indicates that there is no evidence 

of increased quantitative or qualitative susceptibility of the offspring after in utero or postnatal exposure. Based on this information, OSKU believes that there is no concern, at this 

time, for increased sensitivity to infants and children to sulfur dioxide and sodium 

metabisulfite when used on posthaverst blueberries. 

F. International Tolerances

There is currently no Maximum Residue Level (MRL) established for sulfur dioxide on 

blueberries by the Codex Alimentarius Commission. However, OSKU is aware that New 

Zealand and the European Community are considering the inclusion of the use of sulfur 

dioxide on blueberries with permitted sulfur dioxide residues of up to 10 ppm.