April 21, 2014

Mr. Charles E. Barbieri
Foster Swift Collins & Smith PC
313 S. Washington Square
Lansing, Michigan 48933

Dear Mr. Barbieri:

Thank you for your November 27, 2013, letter to the Occupational Safety and Health Administration's (OSHA) Directorate of Enforcement Programs with your question regarding OSHA's Methylenedianiline (MDA) standard, 29 CFR 1910.1050. This letter constitutes OSHA's interpretation only of the requirements discussed and may not be applicable to any question not delineated within your original correspondence. For clarification, your specific questions are paraphrased below, followed by OSHA's responses.

Background: Your client is requesting an interpretation of the definition of what constitutes a salt of MDA as it applies to paragraph 1910.1050(b), which states:

4,4' Methylenedianiline or MDA means the chemical, 4,4'-diaminodiphenylmethane, Chemical Abstract Service Registry number 101-77-9, in the form of a vapor, liquid, or solid. The definition also includes the salts of MDA.

Note, the above definition of MDA and its salts at 1910.1050(b) is the same one used in the construction industry, per 29 CFR 1926.60, and the shipyard industry, per 29 CFR 1915.1050.

Also note, per Appendix A to 1910.1050, MDA can affect your health if you inhale it or if it comes in contact with your skin or eyes. Short-term (acute) overexposure to MDA may produce fever, chills, loss of appetite, vomiting, jaundice, and skin sensitization. Repeated or prolonged (chronic) exposure to MDA, even at relatively low concentrations, may cause cancer. In addition, damage to liver, kidneys, and spleen may occur with long-term exposure to MDA.

Question 1: Is MDA that is complexed with sodium chloride (NaCl) considered a salt of MDA, as defined in paragraph 1910.1050(b), and thus regulated under OSHA's MDA standard?

Response: OSHA's definition in paragraph 1910.1050(b), above, includes the salts of MDA. OSHA interprets this to include organic salts that result from MDA being complexed with an alkali metal salt. Alkali metal salts include, but are not limited to, sodium chloride, sodium bromide, sodium iodide, lithium chloride, lithium bromide, lithium iodide, and sodium cyanide. In your letter, you appropriately pointed out that when MDA is complexed with NaCl, the resulting complex does not meet the ordinary acid-base definition of a salt. However, the complex formed by MDA and NaCl is considered a complex neutral organic amine salt that may be expressed as MDA:NaCl [3:1]. Since OSHA considers this to be a salt of MDA, then where there are occupational exposures, it would be regulated under the MDA standard. The only exceptions to this are provided in paragraphs 1910.1050(a)(2) through (a)(7).

Question 2: Is MDA complexed with NaCl in the two chemical product examples, below, regulated under OSHA's MDA standard?

• Chemical Product 1: Contains MDA, mixed with the MDA salt described above, having a weight or volume of about 50%, with free MDA having a final weight or volume less than or equal to 2%.
• Chemical Product 2: Contains MDA, mixed with the MDA salt described above, having a weight or volume of about 50%, with free MDA having a final weight or volume less than 0.1%.

Response: Our response to question 1 established that MDA:NaCl [3:1] is considered a salt of MDA and falls within the scope of the standard. Whether use of these two products would be regulated by the MDA standard depends on whether any of the exemptions in paragraphs (a)(2) through (a)(7) apply. For example, 1910.1050(a)(6), for MDA, states:

[T]his section does not apply to materials in any form which contain less than 0.1 percent MDA by weight or volume.

In your chemical product examples, you are diluting MDA with an MDA salt, and since both chemicals are included in the scope of the MDA standard, the resulting mixture would be expected to have a weight or volume greater than 0.1 percent and so the (a)(6) exemption, above, would not apply.

Furthermore, as this MDA salt is only moderately stable, it will readily decompose back into MDA and NaCl when exposed to moisture (humidity), light, or elevated temperature. When conditions used in the industrial process release MDA from its salt complex, workers may receive hazardous exposures to MDA. Thus, the two chemical products used as examples would be regulated under the MDA standard where there is occupational exposure and if the other exemptions do not apply.

Please be aware that since you are located in Michigan, which is a State Plan state, the Michigan Occupational Safety and Health Administration (MIOSHA) is charged with promoting the "health, safety and general well-being" of all of its employees. Michigan may have its own enforceable state standards that are equivalent to or stricter than federal standards. Please contact MIOSHA for its specific requirements regarding your situation. MIOSHA can be contacted at:

Michigan Department of Licensing and Regulatory Affairs
Michigan Occupational Safety and Health Administration
P.O. Box 30643
7150 Harris Drive
Lansing, MI 48909-8143
Phone: (800) 866-4674
Web: www.osha.gov/dcsp/osp/stateprogs/michigan.html

Thank you for your interest in occupational safety and health. We hope this provides the clarification you were seeking. OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at www.osha.gov. If you have any further questions, please feel free to contact the Office of Health Enforcement at (202) 693-2190.

Sincerely,

Thomas Galassi, Director
Directorate of Enforcement Programs