Q1. Are aerosols and gases that are being shipped by domestic vessel included in the marine pollutant exception offered in § 171.4(c)(2), or are they prohibited from taking advantage of this marine pollutant exception? You present an example consisting of a package of flammable gas aerosols that qualify as limited quantities, but also contain 30% heptane, a material listed in Appendix B to § 172.101.

A1. The answer to your question is no. The exceptions provided in § 171.4(c)(2) apply to single or combination packagings containing a net quantity per single or inner packaging of 5 L or less for liquids or having a net mass of 5 kg or less for solids. Gases that are listed marine pollutants in Appendix B to § 172.101 may not utilize these exceptions.

Q2. You ask if you may take the marine pollutant exception in § 171.4(c)(2) for "UN 1950 Aerosols, 2.1, Limited Quantity" to receive exception from the marine pollutant requirements for domestic vessel transportation.

A2. No. See A1 above.

Q3. Are aerosols as defined in § 171.8 liquids, solids or gases?

A3. Section § 171.8 defines an aerosol as "any non-refillable receptacle containing a gas compressed, liquefied or dissolved under pressure, the sole purpose of which is to expel a nonpoisonous (other than a Division 6.1 Packing Group III material) liquid, paste, or powder and fitted with a self-closing release device allowing the contents to be ejected by the gas." While aerosols may contain a liquid, paste, or powder, they are considered gases for the purposes of the HMR.

Q4. You ask if you can take the marine pollutant exception in § 171.4(c)(2) for transportation by domestic vessel of gases that meet the definition of a marine pollutant. You present an example of "UN 1064, Methyl Mercaptan, 2.3 (2.1)."

A4. No. See A1.

Q5. If I can take the exception in § 171.4(c)(2) for domestic vessel transportation of limited quantity aerosols that also meet the definition in § 171.8 of a marine pollutant, what are all the hazardous material markings, labels, placards, and shipping paper description requirements that are required for domestic vessel transportation?

A5. No. See A1.

Q6. If I cannot take the exception in § 171.4(c)(2) for domestic vessel transportation of limited quantity aerosols that also meet the definition in § 171.8 of a marine pollutant, what are the hazardous material marking, labeling, placarding, and shipping paper description requirements that are required for domestic vessel transportation?

A6. All hazard communication requirements of the HMR that generally apply to vessel shipments of limited quantity and marine pollutants apply.

Q7. The IMDG Code in 2.10.2.7 has a similar exception for marine pollutants to the HMR § 171.4(c)(2) exception. Are the HMR exceptions related to aerosols and gases consistent with this exception in the IMDG Code?

A7. Yes. The HMR is consistent with the IMDG Code exception for marine pollutants.

Q8. You present a scenario consisting of a package that contains a substance that meets the definition of a hazardous substance and a marine pollutant in § 171.8 that also meets the criteria to be offered as a limited quantity, and ask what are the hazardous materials marking, labeling, placarding, and shipping paper description requirements when this package is offered for transportation by domestic vessel. Specifically, you state you have a combination package containing "UN3077, Environmentally hazardous substance, solid, n.o.s., 9, III," containing 30% Carbaryl, a marine pollutant, and 70% Trifluralin, a hazardous substance.

A8. All hazard communication requirements of the HMR that generally apply to vessel shipments of limited quantity, marine pollutant, and environmentally hazardous substance shipments apply. Marking requirements include the general marking requirements for non-bulk packagings (i.e. proper shipping name and UN identification number), see § 172.301, the marking of the name of the components in the mixture that are a hazardous substance and a marine pollutant, see §§ 172.324 and 172.322, the marking of the package with the letters "RQ", see § 172.324, the limited quantity marking on both the package and the cargo transport unit, see § 172.315, and the marine pollutant marking on both the package and the cargo transport unit, see §172.322. This package would require a Class 9 label, see § 172.400. For domestic transportation of Class 9 material no placard is required, see § 172.504. Several of the additional description requirements required on shipping papers are authorized to be placed in multiple locations, either before or after or in association with the basic description. An example of one appropriate shipping paper description would be "RQ, UN3077, Environmentally hazardous substance, solid, n.o.s. (Carbaryl, Trifluralin), 9, III, Limited Quantity, Marine Pollutant," but as noted some of the additional description requirements required for this shipment are authorized to be placed in other locations, see § 172.203.