UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL 

SAFETY AND 

POLLUTION PREVENTION

Wednesday, April 20, 2011

MEMORANDUM

Subject: Acute Toxicity Review for EPA Reg. No.: 85808-R

DP Barcode: D384435

Product Name: Stabicide 71

From: Ian Blackwell, Biologist

Chemistry and Toxicology Team

Product Science Branch

Antimicrobials Division (7510P)

Through: Karen Hicks, Team Leader

Chemistry and Toxicology Team

Product Science Branch

Antimicrobials Division (7510P)

To: Marshall Swindell, PM 33/ Demson Fuller 

Regulatory Management Branch 

Antimicrobials Division (7510P)

Applicant: Schulke & Mayr GmbH 

FORMULATION FROM LABEL:

Active Ingredient(s): % by wt.

N , N’- methylenebis (5-methyloxazolidin) (MBO) 99.09

Other Ingredient(s): 0.91

Total: 100.00
I BACKGROUND: Schulke & Mayr GmbH has submitted an acute inhalation toxicity study 

to support a data gap for their product, “Stabicide 71”. The Chemistry and Toxicology 

Team (CTT) conducted a review of 85808-R on 3/3/2009. The results of that review 

were:

Study MRID Number Toxicity Category Status

Acute Oral Toxicity 475972-03 III Acceptable

Acute Dermal Toxicity 475972-04 II Acceptable

Acute Inhalation Toxicity Waiver Request ? Data Gap

Primary Eye Irritation 475972-05 I Acceptable

Primary Skin Irritation 475972-05 I Acceptable

Dermal Sensitization 475972-06 Non-sensitizer Acceptable

The Fraunhofer Institute for Toxicology and Experimental Medicine (ITEM) conducted 

this study. Prof. Dr. Dr. U. Heinrich is the author. 

II RECOMMENDATIONS: 

1. CTT grades this study Supplementary. This study is not currently acceptable; but,

can be upgraded with the addition of more information. CTT needs for the test 

facility to answer or address each of the following: 

A. The report does not state whether the test material was tested neat or diluted. 

The registrant needs to clarify this. 

B. The size of the exposure chamber was not reported. 

C. The lab did not conduct the assay by analyzing the chamber concentration of the 

active ingredient, N, N’-methylenebis (5-methyloxazolidin). Instead the report 

states, “Formaldehyde was used as the lead compound for analysis.” We do 

realize that MBO is a reaction product from paraformaldehyde and 2-

hydroxypropylamine. CTT knows from the Product Chemistry review of 85808-

R, that one method of measuring MBO concentration is by reacting it with 

hydroxylamine hydrochloride. The report does not state how the assay went 

from measuring the atmospheric aerosol concentration 85808-R to having 

gaseous formaldehyde in the impingers. These things need to be clarified. 

D. The test facility did not determine the Mass Median Aerodynamic Diameter

(MMAD) of the aerosol. The report appears to state that due to evaporation of 

the aerosolized product, they could not measure the MMAD. CTT does not 

understand why they could determine a test material concentration (mg/L), but,

could not determine an MMAD. The lab needs to explain this. 

E. As there was an issue with vaporization of the aerosol, CTT must ask if the lab 

intentionally vaporized the test material for testing. 
The acute toxicity profile for File Symbol 85808-R is currently:

Study MRID Number Toxicity Category Status

Acute Oral Toxicity 475972-03 III Acceptable

Acute Dermal Toxicity 475972-04 II Acceptable

Acute Inhalation Toxicity 482860-02 ? Supplementary

Primary Eye Irritation 475972-05 I Acceptable

Primary Skin Irritation 475972-05 I Acceptable

Dermal Sensitization 475972-06 Non-sensitizer Acceptable

III LABELING: 

1. The Signal Word is “DANGER”, based upon the results of the primary eye and skin 

irritation studies. 

2. Other than the Signal Word, CTT cannot prescribe Precautionary labeling for 85808-

R. Upon the receipt of supplemental information on the acute inhalation toxicity 

study, CTT might be able to complete the acute toxicity profile and prescribe 

complete precautionary labeling. 
DATA REVIEW FOR ACUTE INHALATION TOXICITY (§81-3, 870.1300)

Testing Laboratory: Fraunhofer Institute for Toxicology and Experimental Medicine 

(ITEM) 

 Author: Prof. Dr. Dr. U. Heinrich

Quality Assurance (40 CFR §160.12): Included

Test Material: Stabicide 71, (Grotan OX)

Concentration: 0.543 and 1.189 mg/L 

Species: Wistar rats, Crl:WI(WU)

Weight: Males= 241.9-302.7 g Females= 188.1-197.8 g

Age: 8-10 weeks

 Source: Charles River Deutschland

Summary:

1. LC50 (mg/L) Males= Unknown

Females= Unknown

Combined= n/a

2. The estimated LC50 is Unknown

3. MMAD: Not determined μm

4. Toxicity Category: Classification: Supplementary

Procedure (Deviation From §81-3):

 The lab planned to use a 0.05 mg/L exposure dosage; however, this was not used. 

Results:

Reported Mortality

Exposure Concentration

(mg/L)

(NUMBER DEATHS/NUMBER TESTED)

Males Females Combined

0.543 0/3 0/3 0/6

1.189 3/3 0/3 3/6

Product Manager: 33 Reviewer: I. Blackwell

MRID No.: 482860-02 Study Completion Date: 10/22/2010

 Lab Study No.: 02 G 10026
Chamber Atmosphere

Dose Level MMAD GSD particles < μm

0.543 mg/L ? μm ? μm ?

1.189 mg/L ? μm ? μm ?

Chamber Environment

Chamber Volume ? ?

Airflow 17.6 L/min. 17.6 L/min.

Temperature 21.3 ± 0.1o C 21.3 ± 0.1o C

Relative Humidity 61.2 ± 0.7 % 63.1 ± 0.6 %

Clinical Observations: Salivation, stains around mouth, coat soiled, gasping, respiratory 

sounds, general condition bad, abdominal breathing. 

Gross Necropsy Findings: Lungs showy areas that were red, partly red, spongy, and/or 

glassy.