Class 6, Toxic and Infectious Substances

2.27 General

Substances are included in Class 6 if they are

(a) liable to cause death or serious injury or to harm human health if swallowed or inhaled or if they come into contact with human skin; or

(b) infectious substances.

2.28 Divisions

Class 6 has two divisions:

(a) Class 6.1, Toxic Substances, which consists of substances that are liable to cause death or serious injury or to harm human health if swallowed or inhaled or if they come into contact with human skin; and

(b) Class 6.2, Infectious Substances, which consists of infectious substances.

2.29 Criteria for Inclusion in Class 6.1, Toxic Substances

Substances included in Class 6.1, Toxic Substances, are grouped by oral toxicity, dermal toxicity and inhalation toxicity by mist or dust or by vapour. Toxicity by inhalation of a gas is covered in Class 2.3, toxic gases.

A substance is included in Class 6.1

(a) due to oral toxicity if

(i) it is a solid and its LD₅₀ (oral) is less than or equal to 200 mg/kg, or

(ii) it is a liquid and its LD₅₀ (oral) is less than or equal to 500 mg/kg;

(b) due to dermal toxicity if its LD₅₀ (dermal) is less than or equal to 1 000 mg/kg; or

(c) due to inhalation toxicity

(i) by dust or mist if dust or mist is likely to be produced in a transport accident and its LC₅₀ (inhalation) is less than or equal to 10 mg/L, or

(ii) by vapour if its LC₅₀ (inhalation) is less than or equal to 5 000 mL/m³.

(1) When a substance is known to be included in Class 6.1 and that knowledge is supported by documentary evidence published in technical journals or government publications and testing is not done to determine the packing group, the substance must be included in Packing Group I.

(2) Substances that are included in Class 6.1 due to

(a) oral toxicity are included in the following packing groups:

(i) Packing Group I, if the LD₅₀ (oral) is less than or equal to 5 mg/kg,

(ii) Packing Group II, if the LD₅₀ (oral) is greater than 5 but less than or equal to 50 mg/kg, and

(iii) Packing Group III, if the LD₅₀ (oral) is greater than 50 mg/kg;

(b) dermal toxicity are included in the following packing groups:

(i) Packing Group I, if the LD₅₀ (dermal) is less than or equal to 40 mg/kg,

(ii) Packing Group II, if the LD₅₀ (dermal) is greater than 40 but less than or equal to 200 mg/kg, and

(iii) Packing Group III, if the LD₅₀ (dermal) is greater than 200 mg/kg;

(c) inhalation toxicity by dust or mist are included in the following packing groups:

(i) Packing Group I, if the LC₅₀ (inhalation) is less than or equal to 0.5 mg/L,

(ii) Packing Group II, if the LC₅₀ (inhalation) is greater than 0.5 but less than or equal to 2 mg/L, and

(iii) Packing Group III, if the LC₅₀ (inhalation) is greater than 2 mg/L; and

(d) inhalation toxicity by vapour are included in the following packing groups, where "V" is the saturated vapour concentration in millilitres per cubic metre of air at 20º C and at 101.3 kPa:

(i) Packing Group I, if

(A) V is greater than or equal to 10 multiplied by the LC₅₀, and

(B) the LC₅₀ is less than or equal to 1 000 mL/m³,

(ii) Packing Group II, if

(A) V is greater than or equal to the LC₅₀,

(B) the LC₅₀ is less than or equal to 3 000 mL/m³, and

(C) the criteria for Packing Group I are not met, and

(iii) Packing Group III, if

(A) V is greater than or equal to 0.2 multiplied by the LC₅₀,

(B) the LC₅₀ is less than or equal to 5 000 mL/m³, and

(C) the criteria for inclusion in Packing Group I or II are not met.

2.31 Determination of LD₅₀ (oral or dermal)

LD₅₀ (oral or dermal) values for solid or liquid substances or for a mixture of solid or liquid substances must be determined

(a) by using the LD₅₀ values published in technical journals or in government publications;

(b) in accordance with section 2.6.2.3 of Chapter 2.6 of the UN Recommendations; or

(c) for a mixture of solid or liquid substances, in accordance with section 2.32.

2.32 Determination of LD₅₀ (oral or dermal) for a Mixture of Substances

This section provides an acceptable approximation of the LD₅₀ of a mixture of solid or liquid substances. The methods in paragraphs 2.31(a) and (b) are more exact.

To determine the LD₅₀ of a mixture of solid or liquid substances when the LD₅₀ of each of the substances is known, use 1 000 mg/kg as the toxic limit and

(a) if the mixture contains only one substance with an LD₅₀ less than or equal to the toxic limit (called Substance A), use the following calculation:

(b) if the mixture contains more than one substance with an LD₅₀ less than or equal to the toxic limit (called Substance A, Substance B,…),

(i) determine the lowest LD₅₀ of all substances, assign that LD₅₀ to all substances whose actual LD₅₀ is less than or equal to the toxic limit, then use the calculation in paragraph (a) using that assigned LD₅₀ and taking as the mass of Substance A in the formula the total of the masses of all substances whose actual LD₅₀ is less than or equal to the toxic limit, or

(ii) use the following the calculations:

(A) determine the contributing number (CN) of each of the substances with an LD₅₀ less than or equal to the toxic limit in accordance with the formula,

(B) combine the contributing numbers (CN) of each substance with an LD₅₀ less than or equal to the toxic limit as

(C) obtain the LD₅₀ of the mixture by dividing 1 by the number T (LD₅₀ of the mixture = 1 /T).

2.33 Determination of LC₅₀ (mist, dust or vapour)

LC₅₀ values (inhalation of mist, dust, or vapour) for a substance in the form of a mist, dust or vapour or for a mixture of substances in the form of a mist, dust or vapour must be determined

(a) by using the LC₅₀ values published in technical journals or in government publications;

(b) in accordance with sections 2.6.2.2.4.2 to 2.6.2.2.4.7 of Chapter 2.6 of the UN Recommendations; or

(c) for a mixture of substances, in accordance with section 2.34.

2.34 Determination of LC₅₀ (mist, dust or vapour) for a Mixture of Substances

This section provides an acceptable approximation of the LD₅₀ of a mixture of substances. The methods in paragraphs 2.33(a) and (b) are more exact.

To determine the LC₅₀ of a mixture of substances that are in the form of a mist, dust or vapour, when the LC₅₀ of each of the substances is known, make the determination in accordance with section 2.17, except that for a mist use 2 mg/L as the toxic limit and for a dust use 10 mg/L as the toxic limit. For a substance in the form of vapour the toxic limit is the same as for a gas, 5 000 mL/m³.

(1) The first step in determining the packing group of a mixture of liquids with an inhalation toxicity by vapour when one or more substances has an LC₅₀ (vapour) less than or equal to 5 000 mL/m³, and the LC₅₀ of each substance is known, is to determine the following data:

(a) determine the LC₅₀ (vapour) for the mixture in accordance with section 2.34;

(b) where P_i is the vapour pressure of the i^th substance in kPa at 20^oC and an absolute pressure of 101.3 kPa, determine the volatility, V_i, of each substance in the mixture as

V_i = P_i multiplied by 10⁶ then divided by 101.3;

(c) determine the ratio of the volatility of a substance to its LC₅₀ for each substance with an LC₅₀ less than or equal to 5 000 mL/m³ as

R_i = V_i divided by the LC₅₀ of the i^th substance; and

(d) set R equal to the sum of the R_i for each of the substances with an LC₅₀ less than or equal to 5 000 mL/m³ as

R = R₁ + R₂ + …+ (as needed).

(2) Using the data determined in accordance with subsection (1), the mixture is included in one of the following packing groups:

(a) Packing Group I, if

(i) R is greater than or equal to 10, and

(ii) LC₅₀ (mixture) is less than or equal to 1 000 mL/m³;

(b) Packing Group II, if

(i) R is greater than or equal to 1,

(ii) LC₅₀ (mixture) is less than or equal to 3 000 mL/m³, and

(iii) the criteria for inclusion in Packing Group I are not met; and

(c) Packing Group III, if

(i) R is greater than or equal to 0.2,

(ii) LC₅₀ (mixture) is less than or equal to 5 000 mL/m³, and

(iii) the criteria for inclusion in Packing Group I or II are not met.

2.36 Determination of the Packing Group of a Mixture of Liquids with an Inhalation Toxicity and an
Unknown LC₅₀

This section provides a method of directly determining the packing group of a mixture of liquids that has an inhalation toxicity without requiring that the exact LC₅₀ be found.

(1) A mixture of liquids with an inhalation toxicity and an unknown LC₅₀ is included in Packing Group I if it meets the following criteria:

(a) when a sample of the mixture is vapourized and diluted with air to create a test atmosphere of 1 000 mL/m³ and 10 albino rats (5 male and 5 female) are exposed to the test atmosphere for 1 hour and observed for 14 days, the result is the death of 5 or more of the animals within the 14 day observation period; and

(b) when a sample of the vapour in equilibrium with the mixture at 20°C is diluted with 9 equal volumes of air to form a test atmosphere and 10 albino rats (5 male and 5 female) are exposed to the test atmosphere for 1 hour and observed for 14 days, the result is the death of 5 or more of the animals within the 14 day observation period.

In this case the mixture is presumed to have an LC₅₀ less than or equal to 1 000 mL/m³ and a volatility greater than or equal to 10 times the mixture’s LC₅₀.

(2) A mixture of liquids with an inhalation toxicity and an unknown LC₅₀ is included in Packing Group II if it meets the following criteria and the criteria for inclusion in Packing Group I are not met:

(a) when a sample of the mixture is vapourized and diluted with air to create a test atmosphere of 3 000 mL/m³ and 10 albino rats (5 male and 5 female) are exposed to the test atmosphere for 1 hour and observed for 14 days, the result is the death of 5 or more of the animals within the 14 day observation period; and

(b) when a sample of the vapour in equilibrium with the mixture at 20°C is used to form a test atmosphere and 10 albino rats (5 male and 5 female) are exposed to the test atmosphere for 1 hour and observed for 14 days, the result is the death of 5 or more of the animals within the 14 day observation period.

In this case the mixture is presumed to have an LC₅₀ less than or equal to 3 000 mL/m³ and a volatility greater than or equal to the mixture’s LC₅₀.

(3) A mixture of liquids with an inhalation toxicity and an unknown LC₅₀ is included in Packing Group III if it meets the following criteria and the criteria for inclusion in Packing Group I or II are not met:

(a) when a sample of the mixture is vapourized and diluted with air to create a test atmosphere of 5 000 mL/m³ and 10 albino rats (5 male and 5 female) are exposed to the test atmosphere for 1 hour and observed for 14 days, the result is the death of 5 or more of the animals within the 14 day observation period; and

(b) when the vapour pressure of the mixture is measured, the vapour concentration is greater than or equal to 1 000 mL/m³.

In this case the mixture is presumed to have a volatility greater than or equal to 0.2 times the mixture’s LC₅₀ and the mixture is presumed to have an LC₅₀ less than or equal to 5 000 mL/m³

2.37 Risk Groups for Class 6.2, Infectious Substances

(a) Risk Group IV, if they are included in the list of Risk Group IV substances in Appendix 2 to this Part or if they exhibit characteristics similar to those substances, including the following:

(i) the disease they cause has serious effects that may be irreversible or lethal in humans who or animals that have contracted the disease, and

(ii) that the micro-organisms are readily transmitted from an infected human or animal to an uninfected human or animal, directly or indirectly or by casual contact;

(b) Risk Group III, if they are included in the list of Risk Group III substances in Appendix 2 to this Part or if they exhibit characteristics similar to those substances, including the following:

(i) the disease they cause seriously affects the health of humans who or animals that have contracted the disease,

(ii) the micro-organisms are not readily transmitted from an infected human or animal to an uninfected human or animal by casual contact, and

(iii) the disease they cause can be treated by antimicrobial or antiparasitic agents; and

(c) Risk Group II, if they are included in the list of Risk Group II substances in Appendix 2 to this Part or if they exhibit characteristics similar to those substances, including the following:

(i) the disease they cause does not seriously affect the health of humans who or animals that have contracted the disease,

(ii) the micro-organisms are rarely transmitted from an infected human or animal to an uninfected human or animal by direct contact, and

(iii) there exists readily available treatment for humans and animals that have contracted the disease they cause.