(c) It is aqueous and has a pH in aqueous solution less than or equal to 2 as determined by the test method
specified in Title 40 CFR, Section 261.22.
C2 - Acid, Corrosive, Organic. An acid (hydrocarbon based), either liquid or solid, meeting the definition of a
Corrosive Material (UN Class 8) under DOT Title 49, Section 173.136, or EPA 40 CFR 370.2, or OSHA 29 CFR
1910.1200, Appendix A that causes visible destruction or irreversible alterations in human skin tissue at the site
of contact, or a liquid that has a severe corrosion rate on steel or aluminum, in accordance with any one of the
following criteria:
(a) A material is considered to be destructive or to cause irreversible alteration in human skin tissue if, when
tested on the intact skin of an albino rabbit, the structure of the tissue at the site of contact is destroyed or changed
irreversibly after an exposure period of 4 hours or less; or
(b) A liquid is considered to have a severe corrosion rate if its corrosion rate exceeds 6.25 mm (0.246 inches)
per year on steel (SAE 1020) or aluminum (nonclad 7075-T6) at a test temperature of 55oC (131oF). An
acceptable test is described in NACE standard TM-01-69; or
(c) It is aqueous and has a pH in aqueous solution less than or equal to 2 as determined by the test method
specified in Title 40 CFR, Section 261.22.
C3 - Acid, Low Risk. A liquid or solid product that exhibits acidic properties and does not meet the definition of
HCCs C1 or C2 but which through experience or through documentation on the MSDS or product bulletin would
cause severe skin or eye irritation, dermatitis, or allergic skin reaction. Any classification of a material into this
category is a process which relies heavily on the professional judgment of the evaluator recognizing that
individuals react differently to exposure to chemicals. Factors to consider are the pH, the intended use of the
product, the type of package, and the concentration of the active ingredient(s).
C4 - Acid, Corrosive and Oxidizer, Inorganic. An inorganic acid (HCC C1) that also meets the definition of
an Oxidizer (HCC D1).
C5 - Acid, Corrosive and Oxidizer, Organic. An organic acid (HCC C2) that also meets the definition of an
Oxidizer (HCC D1).
D1 - Oxidizer. A material regulated as an Oxidizer, UN Class 5.1, by DOT under 49 CFR 173.127 or is listed in
Section 43A of the National Fire Protection Association (NFPA) Fire Codes Subscription Service as a Class 1, 2,
3, or 4 oxidizer other than a compressed gas, that can undergo an explosive reaction when catalyzed or exposed to
heat, shock, or friction; or will cause a severe increase in the burning rate of combustible material with which it
comes in contact; or which will undergo vigorous self-sustained decomposition when catalyzed or exposed to
heat; or will moderately increase the burning rate or which may cause spontaneous ignition of combustible or
flammable material with which it comes in contact.
D2 - Oxidizer and Poison. An oxidizing material (HCC D1), other than a compressed gas (HCC G4), that also
meets the definition of a poison (HCCs T1, T2, T3, or T4).
B-5
