Interpretation Response #25-0083
Below is the interpretation response detail and a list of regulations sections applicable to this response.
Interpretation Response Details
Response Publish Date:
Company Name: EMD Electronics
Individual Name: Jeanne Enaux
Location State: NJ Country: US
View the Interpretation Document
Response text:
January 7, 2026
Jeanne Enaux
Head of Product Compliance US
EMD Electronics
116 Fairfield Road
Princeton, NJ 08540
Reference No. 25-0083
Dear Ms. Enaux:
This letter is in response to your June 23, 2025 email requesting clarification of the Hazardous Materials Regulations (HMR; 49 CFR Parts 171-180) applicable to the term "surfactant" with respect to the use of "UN2927, Toxic liquid, corrosive, organic, n.o.s." for solutions containing tetramethylammonium hydroxide (TMAH). You ask whether a surfactant includes all substances that can potentially accelerate dermal uptake, or if the term refers only to substances that have hydrophobic-hydrophilic capability.
For the purposes of classifying a non-aqueous solution of TMAH, the HMR does not define the term "surfactant." However, the term generally refers to amphiphilic substances (containing both hydrophobic and hydrophilic parts), which reduce surface tension in liquids, and not the substances' potential to accelerate dermal uptake. In accordance with § 173.22 of the HMR, it is the shipper's responsibility to properly classify a hazardous material. Note that if a mixture contains a substance that can potentially accelerate dermal uptake, the shipper must use the classification criteria of the HMR to classify the mixture and then select a proper shipping name (e.g., UN2927, Toxic liquid, corrosive, organic, n.o.s.) in accordance with § 172.101(c)(10).
I hope this information is helpful. Please contact us if we can be of further assistance.
Sincerely,
Dirk DerKinderen
Chief, Standards Development Branch
Standards and Rulemaking Division
§ 172.101(c)(10), § 173.22