How is a surface disinfectant containing didecyldimethylammonium chloride (DDAC) regulated in the EU, Spain and the US: active substance approval status by product type, the authorisation route, and the relevant register entries?

Summary: In the EU, DDAC (EC 230-525-2, CAS 7173-51-5) is an approved active substance for PT2, the product type that covers surface disinfectants. So a surface disinfectant now needs a product authorisation under the Biocidal Products Regulation. In Spain, products already on the market under national rules can stay there only during the transitional period, and which national authority handles them depends on where the product is used. In the US, the product needs a FIFRA registration with EPA, and DDAC itself is going through EPA's registration review.

Approach: I searched ECHA's list of BPR active substances, the BPC opinions, the R4BP list of authorised products, the Article 95 supplier list, Spain's official biocides register (Registro Oficial de Biocidas), the Ministerio de Sanidad guidance and AEMPS notices, and the EPA lists and 40 CFR 180. The US registration-review and Massachusetts points come from search snippets of official EPA, Federal Register and mass.gov pages.

EU (BPR, Reg. (EU) 528/2012): approval status by product type

DDAC, BAS 67 (evaluating authority: Italy)

PT	Status	Approval period	Legal act
PT1	Approved	2024-02-01 to 2034-01-31	32022R1991 [1]
PT2	Approved	2024-02-01 to 2034-01-31	32022R1991 [2]
PT3	Approved	2022-11-01 to 2032-10-31	32021R1045 [3]
PT4	Approved	2022-11-01 to 2032-10-31	32021R1045 [4]
PT8	Approved, renewal in progress	2015-02-01 to 2027-07-31	32024D2411 [5]
PT6, PT10, PT11, PT12	First approval still under assessment	none	none [6][7][8][9]

ECHA lists DDAC as not a candidate for substitution in PT1-4. For PT8 that point is still under assessment.

The C8-10 grade is a separate active substance. DDAC (C8-10), EC 270-331-5 / CAS 68424-95-3 (BAS 1371), is still under assessment for PT1, PT2, PT3, PT4, PT6, PT10, PT11 and PT12. It is "no longer supported" for PT5 ^[10][11]. Check which grade your product's supplier documents name, because that decides whether the product is already in the BPR product-authorisation phase or still under national transitional rules.

BPC opinion for PT2 (ECHA/BPC/312/2021, adopted 2 December 2021, by consensus):

• The assessed use was professional hard-surface disinfection by coarse spray, followed by rinsing. In-use concentrations were 0.1% or 0.5% ^[12][13].
• Minimum purity is 908 g/kg dry weight. Product assessment must pay particular attention to professional users ^[14].
• Fine sprays (droplets under 40 µm) may need a separate inhalation risk assessment at product authorisation ^[15].
• Current classification is Acute Tox. 4 and Skin Corr. 1B. The proposed classification is Acute Tox. 3, Skin Corr. 1B, Eye Dam. 1, STOT SE 3, Aquatic Acute 1 (M = 10) and Aquatic Chronic 2 ^[16][17].
• Resistance-management strategies may be reviewed at product authorisation ^[13].

Authorisation route:

• The product can be authorised nationally (with mutual recognition into other countries), or as a Union authorisation ^[18].
• The DDAC supplier must be on the Article 95 list for PT2. Eight suppliers are listed, including THOR Especialidades S.A. (Spain), Stepan Europe, Nouryon Surface Chemistry AB, and Mason Chemical (through Technology Sciences Group France) ^{[19][20][21][22]}.

R4BP entries: I found no PT2 product authorisations naming DDAC. The nine DDAC authorisations I found are eight wood preservatives (PT8) and one veterinary hygiene product, BE-0034816-0000 (PT3, Belgium and Germany) ^[23].

Spain

Which authority handles a surface disinfectant

Intended use	Authority and route
Non-clinical surfaces: general/environmental, food industry (TP2)	Ministerio de Sanidad. BPR authorisation through R4BP3 and IUCLID. Spanish companies must attach their ROESB (biocides establishments register) registration [18]. A separate national fee covers TP2 products with existing active substances still under review [24]
Clinical or surgical surfaces with no direct patient contact	AEMPS authorisation under RD 3349/1983 / RD 1054/2002, with a "nº-DES" number on the label [25][26]
Disinfectants intended specifically for medical devices	Not a biocide. Regulated as a medical device under the MDR (Regulation (EU) 2017/745), class IIa or IIb [27]

Transitional rules for products already on the Spanish market

• These are products registered under RD 3349/1983 or RD 1054/2002.
• They can stay on the market for up to three years from approval of the last active substance in them. The condition is that a BPR application (Art. 89(2)) was submitted before that approval date and the product was declared in R4BP3.
• Without an application, sales must stop within 180 days of approval and use within 365 days ^[28].
• For DDAC PT2, approved 1 February 2024, the three years run to 1 February 2027.

Spanish register entries: I found 12 Spanish register entries containing DDAC, DDAC carbonate or the related propionate. All are TP08 wood preservatives, such as ES/APP(NA)-2021-08-00733 ^[29]. One, HYDROKOAT 6, has been cancelled, with sales allowed until 20 June 2027 ^[30]. I found no TP02 entry containing DDAC. The AEMPS list of authorised DES products is not in the data I can search.

United States

Federal registration (FIFRA):

• Each product needs FIFRA Section 3 registration with EPA.
• DDAC's Reregistration Eligibility Decision (RED) was approved on 3 August 2006 (docket EPA-HQ-OPP-2006-0338).
• Registration review is under case 3003, docket EPA-HQ-OPP-2015-0740. The Final Work Plan is dated March 2017.
• I found no official proposed interim decision.

These points come from search snippets of EPA and regulations.gov pages.

Food-contact surfaces (40 CFR 180.940):

• DDAC (CAS 7173-51-5) is exempt from a tolerance on food-processing equipment and utensils up to 200 ppm active quat ^[31].
• Didecyl dimethyl ammonium carbonate/bicarbonate is exempt up to 400 ppm on food-contact surfaces ^[32].

EPA disinfectant lists: List N and EPA's other selected disinfectant lists name the active ingredient only as "Quaternary ammonium", so DDAC products can't be picked out from them. Examples are 1839-216 (Stepan) and 6836-347 (Arxada) ^[33][34].

Massachusetts: mass.gov snippets show a proposed amendment to 301 CMR 41.03 adding a DDAC/ADBAC category to the toxics use reduction (TURA) list from reporting year 2027. A hearing was held on 25 July 2025. I could not confirm from an official source that it has been finalised. I did not check state-by-state FIFRA product registration; I can do that next if useful.

Sources:

• EPA archive: DDAC index (PC Code 069149)
• DDAC Final Work Plan, EPA-HQ-OPP-2015-0740
• mass.gov: proposed revisions to 301 CMR 41.03 (2026)
• mass.gov: 2025 TURA public hearing notice on QACs