## EPA-/L) a -Df'/'T- .--~ o®T -aQ'--v Z Re: Fw : Review of 149-44-0 D David Brooks to : Catherine Roman 08/18/2009 07:11 PM Cc: Greg Fritz, Mark Townsend, Victoria Vanroden, .jgarey,~wlrichards $ ~ Hi Catherine: I received a response back fromour contractor and I am in agreement with their assessment . We believe that submitted studies adequately fulfill test rule requirements. If you feel it is necessary to modify our assessments, please let me know what section(s) you would like to have modified and suggested language to include. We have also included this information in HPVIS. Below is a copy of their email to me. Hi Dave, I just reviewed your e-mail and all of the documents that Joan [Gavey] sent me on CAS No. 149-44-0 . As indicated by the e-mail fromCatherine Roman on 8-12-09, the test rule specified that testing wcfs.'to be provided for 99%pure methanesulfinic acid, hydroxyl-, monosodium salt (CAS No. 149-44-0), but"' testing for human health endpoints was performed using this substance at unspecified purity (in the acute mammalian toxicity studies) or using this substance as a dihydrate formthat also may contain stabilizers and impurities. The submitted documents included both a letter and a robust summary section that described the composition of the tested dihydrate formof the test rule chemical . Based on this information, and the physical/chemical properties of and relationship between the anhydrous and hydrated forms of methanesulfinic acid, hydroxyl-, monosodiumsalt described by Laura Morlacci below, I believe that the human health tests that have been conducted for the dihydrate formof this test rule chemical are adequate to characterize the toxicity of the test rule chemical, methanesulfinic acid, hydroxyl-, monosodiumsalt (CAS No. 149-44-0) . _- CID a Bill Richards Contractor to RAD 703-413-9372 (office) 301-717-4199 (cell) From Ullmann's Encyclopedia of Industrial Chemistry: 6.1 . Properties rn c

Sodium hydroxymethanesulfinate [149-44-0] is commercially available as the dihydrate HOCHZSOz Na ~ 2 H20, which crystallizes as white needles, mp 63 °C . Its solubility in water at roomtemperature is 

# CONTAINS NOCBI 

# ,3ay~A®~60 g/100 g. The salt is sparingly soluble in alcohol, and can be easily obtained pure from60 % methanol . In moist air it decomposes slowly to products with noxious odors. Thewater of crystallization is lost upon heating to 120 °C, and then from125 °C the compound undergoes a very exothermic decomposition to methanethiol, hydrogen sulfide, some formaldehyde, and sulfur dioxide, during which the temperature rises to 160 °C. The residue consists of sodiumhydroxymethanesulfonate, sodiumthiosulfate, and sodiumsulfite. In solution the decomposition is pH and temperature dependent . Sodium hydroxymethanesulfinate reacts with sodiumhydrogen sulfite to give sodiumdithionite (Na2SZ04) and sodiumhydroxymethanesulfonate. The hydroxyl group is acidic and susceptible to salt formation. Laura

Laura A. Morlacci, Ph.D. Senior Chemist

2451 Crystal Drive, Suite 804 Arlington, VA 22202 (703) 413-9374 (703) 413-9363 (FAX)

Catherine Roman Hi David, Thanks for the information in your e-m . . . O8/18/2009 05:07:25 PM From : Catherine Roman/DC/USEPA/US To: David Brooks/DC/USEPA/US@EPA Cc: Greg Fritz/DC/USEPA/US@EPA, Victoria Vanroden/DC/USEPA/US@EPA, Mark

Townsend/DC/USEPA/US@EPA Date: 08/18/2009 05:07 PM Subject : Fw

: Review

of 149-44-0 Hi David, Thanks for the information in your e-mail below . I found it very helpful in understanding this situation and whether the data will ultimately be acceptable. I will appreciate any additional information your contractor may provide. In talking to Greg Fritz of ICB about this, he thought it should be noted that any accepted data were "fromtests of the dihydrate."

----- Forwarded by Catherine Roman/DC/USEPA/US on 08/18/2009 04:48 PM -- From : David Brooks/DC/USEPA/USTo:

Cc: Date: Subject: Hi Catherine, Catherine Roman/DC/USEPA/US@EPA

Mark Townsend/DC/USEPA/US@EPA, Victoria Vanroden/DC/USEPA/US@EPA, jgarey@syrres.com 08/18/2009 04:40 PM Re: Fw : Review

of 149-44-0

I amhaving our contractor take a second look at this issue. However, based on my initial discussions, I think our analysis is correct and purity of the substance as described appear to be adequate, and this material would probably be sold as > or = 98%a pure (that is, 98%pure dihydrate, not 98%pure anhydrous compound) . The CAS number 149-44-0 corresponds to the anhydrous form- but keep in mind that TSCA does not recognize hydrates as being separate entities fromthe corresponding anhydrous material, even if the Chemical Abstracts Service assigns different CAS numbers to various hydrated forms of a chemical . In addition, the anhydrous formis probably not available due to the violent decomposition that follows dehydration . Even if one were to prepare the anhydrous form, it would have to be kept under strictly anhydrous conditions in order to prevent the hydrate fromforming again. I asked our contractor to provide a short report on this issue by early next week. Dave