UN1789 hydrochloric acid table entry.

Where UN1789 sits in the table

UN1789 has two rows that differ only by packing group. Packing group II carries the longer special-provision string 386, A3, B3, B15, B133, IB2, N41, T8, TP2, and packing group III carries A3, IB3, T4, TP1. 172.101(f) explains that Packing Groups I, II, and III indicate the degree of danger presented by the material is great, medium, or minor, respectively, so the lower packing group number is the more dangerous grade and gets the tighter air limit.

Class 8 is defined in 173.136(a): a corrosive material is a liquid or solid that causes irreversible damage to human skin at the site of contact within a specified period of time, and a liquid or a solid that may become liquid during transportation that has a severe corrosion rate on steel or aluminum is also corrosive. The table sets the label as 8 and the highway placard, when one is needed, is CORROSIVE from Table 2.

The full rows from the eCFR copy of the table, current through October 29, 2026 and read November 2, 2026, are below. Every value is copied from 49 CFR 172.101; the last column is the regulation's own explanation of the column.

The 172.101 rows, column by column

How the regulation defines the hazard class

173.136(a) says, abridged: ""corrosive material" (Class 8) means a liquid or solid that causes irreversible damage to human skin at the site of contact within a specified period of time. A liquid, or a solid which may become liquid during transportation, that has a severe corrosion rate on steel or aluminum based on the criteria in 173.137(c)(2) is also a corrosive material."

Special provisions on this entry, in the rule's words

Column 7 does not explain itself; each code is defined in 172.102. These are the definitions as printed in the eCFR text for the codes listed on the rows. Where a provision ends with a list of conditions that this page does not reproduce, it says so.

• 386 (PG II): When transported by private motor carrier only, the following corrosive liquids may be packaged in polyethylene bottles with a capacity no greater than 3.785 L (one gallon), further packed inside an open-top, heavy wall, high density polyethylene box (i.e., crate) in a manner that the polyethylene bottles are not subjected to any superimposed weight, and the boxes must be reasonably secured against shifting within the transport vehicle and loaded so as to minimize the possibility of coming in contact with other lading (the listed conditions continue in the rule).
• A3: For combination packagings, if glass inner packagings (including ampoules) are used, they must be packed with absorbent material in tightly closed rigid and leakproof receptacles before packing in outer packagings.
• B3 (PG II): MC 300, MC 301, MC 302, MC 303, MC 305, and MC 306 and DOT 406 cargo tanks and DOT 57 portable tanks are not authorized.
• B15 (PG II): Packagings must be protected with non-metallic linings impervious to the lading or have a suitable corrosion allowance.
• B133 (PG II): Hydrochloric acid concentration not exceeding 38%, in Packing Group II, is authorized to be packaged in UN31H1 or UN31HH1 intermediate bulk containers when loaded in accordance with the requirements of § 173.35(h) of this subchapter.
• IB2 (PG II): Authorized IBCs: Metal (31A, 31B and 31N); Rigid plastics (31H1 and 31H2); Composite (31HZ1).
• N41 (PG II): Metal construction materials are not authorized for any part of a packaging which is normally in contact with the hazardous material.
• IB3 (PG III): Authorized IBCs: Metal (31A, 31B and 31N); Rigid plastics (31H1 and 31H2); Composite (31HZ1 and 31HA2, 31HB2, 31HN2, 31HD2 and 31HH2).

T8, TP2, T4, TP1 are portable tank instructions or provisions, defined in 172.102(c)(7) and (c)(8). They are on the row but are not reproduced on this page.

What else to know about this entry

Three of the packing group II codes are specific to hydrochloric acid handling. B15 says packagings must be protected with non-metallic linings impervious to the lading or have a suitable corrosion allowance. N41 says metal construction materials are not authorized for any part of a packaging normally in contact with the hazardous material. B133 says hydrochloric acid concentration not exceeding 38 percent, in packing group II, is authorized to be packaged in UN31H1 or UN31HH1 intermediate bulk containers when loaded in accordance with 173.35(h).

B3 says MC 300, MC 301, MC 302, MC 303, MC 305, and MC 306 and DOT 406 cargo tanks and DOT 57 portable tanks are not authorized. That is a bulk packaging limit and applies to the packing group II row only. A3 on both rows covers glass inner packagings in combination packagings.

The ERG 2024 index lists two names under UN1789: Hydrochloric acid and Muriatic acid, both with Guide 157 (Substances - Toxic and/or Corrosive (Non-Combustible/Water-Sensitive)). The table row itself uses only the name Hydrochloric acid.

Air quantity limits and a worked example

Columns 9A and 9B give the largest net quantity allowed in one package: column 9A for passenger-carrying aircraft or passenger-carrying rail car, column 9B for cargo aircraft only. 172.101(j) says "Forbidden" means the material may not be offered for transportation or transported in the applicable mode, and that the limit is net unless stated otherwise. For UN1789 the PG II row shows 1 L in column 9A and 30 L in column 9B.

Worked example: a 5 L net package of the PG II row. On a passenger aircraft or passenger-carrying rail car it is over the 1 L limit in column 9A. On a cargo aircraft only it is within the 30 L limit in column 9B. The calculator above applies the same comparison to the quantity you type.

The limits depend on the row, so match the packing group on the shipping paper first: PG II is 1 L in column 9A and 30 L in column 9B; PG III is 5 L in column 9A and 60 L in column 9B.

Highway placard check

Class 8 is on Table 2 of 172.504(e) as CORROSIVE.

For Table 2 materials moved by highway or rail, 172.504(c) says placards are not required on a transport vehicle or freight container that contains less than 454 kg (1,001 pounds) aggregate gross weight of hazardous materials covered by Table 2, except for bulk packagings and hazardous materials subject to 172.505. In the calculator, 1,000 pounds of non-bulk Table 2 material returns "not required" and 1,001 pounds returns "required", and any bulk packaging returns "required". The weight is the aggregate gross weight of all Table 2 materials on the vehicle, not just this one UN number.

Vessel stowage and the ERG guide

Column 10A gives category C (the material must be stowed "on deck only" on a cargo vessel or on a passenger vessel). Column 10B lists 53, 58, 8. Code 53 in 176.84: Stow "separated from" alkaline compounds. Code 58 in 176.84: Stow "separated from" cyanides. Code 8 in 176.84: Glass carboys not permitted on passenger vessels. These apply to shipments by vessel and have no effect on a truck-only move.

The Emergency Response Guidebook 2024 numerical index lists UN1789 under Guide 157, titled "Substances - Toxic and/or Corrosive (Non-Combustible/Water-Sensitive)". 172.101 itself does not list ERG guide numbers; the guide number comes from the PHMSA guidebook. The guide is for first responders during the initial phase of an incident and is not a shipping-paper or compliance document.

What this page does not do

It reproduces the table rows and the regulation text it points to, and applies the air-limit and 1,001 pound placard comparisons to numbers you enter. It does not classify a product, pick a packing group, decide which table row applies to your shipment, or replace the packaging sections the row points to (the 173 sections in columns 8A to 8C), the marking, labelling and shipping paper rules in part 172, or hazmat training. Hazardous materials employees must be trained; that decision and the shipping description belong to a trained person. The eCFR header for 172.101 links an amendment published at 91 FR 49310 (August 4, 2026); confirm that the version you rely on includes the latest changes. In an emergency call 911 and the emergency response telephone number on the shipping paper.

Sources

Sources opened and read November 2, 2026. Regulation text was read from the eCFR API, which publishes the current Code of Federal Regulations.

• 49 CFR 172.101, Hazardous Materials Table (eCFR text current through October 29, 2026; read November 2, 2026)
• 49 CFR 172.102, Special provisions (read November 2, 2026)
• 49 CFR 172.504, General placarding requirements (read November 2, 2026)
• 49 CFR 173.136, hazard class definitions (read November 2, 2026)
• 49 CFR 176.84, Other requirements for stowage, cargo handling, and segregation (read November 2, 2026)
• PHMSA: Emergency Response Guidebook 2024 English PDF, numerical index (read via the Internet Archive capture of October 31, 2026; read November 2, 2026)