School of Infection & Immunity

Toxic Hazard Classification

All materials can be classified into one of four toxic hazard categories:-

Very High (V)

High (H)

Medium (M)

Low (L)

If the resultant hazard classification is Very High or High, try to reduce the hazard by eliminating a material or by using a substitute

and are defined by the following criteria.

Note:

If the resultant hazard classification is Very High or High, try to reduce the hazard by eliminating a material or by using a substitute.

In the following definitions the letter R denotes an EC Risk Phrase.

Very High Hazard V

A material which meets any of the following criteria:

(i) Exposure Standards <0.1 ppm for vapour or <0.1 mg/m3 for dusts

(ii) Is very toxic by acute exposure:

LC50 rat 0.5 mg/L/4hr or less: R26 VERY TOXIC BY INHALATION

Dermal LD50 rat or rabbit £ 50 mg/kg: R27 VERY TOXIC IN CONTACT WITH SKIN

Oral LD50 rat 25 mg/kg or less: R28 VERY TOXIC IF SWALLOWED

(iii) Subacute toxicity with oral no effect level <0.1 mg/kg/day or equivalent dosage by other routes.

(iv) Potent carcinogen: (R45) MAY CAUSE CANCER, (R49) MAY CAUSE CANCER BY INHALATION

(v) Respiratory sensitizer: (R42) MAY CAUSE SENSITISATION BY INHALATION

(vi) Substances of unknown toxicity which after inspection of the structure or of other data are likely to be classified at V by analogy.

High Hazard H

(i) Exposure Standards >0.1 ppm & <10 ppm for vapour or >0.1 mg/m3 and <1 mg/m3 for dusts.

(ii) Is toxic by acute exposure:

LC50 rat 0.5 - 2 mg/L/4hr: R23 TOXIC BY INHALATION

Dermal LD50 rat or rabbit 50 - 400 mg/kg: R24 TOXIC IN CONTACT WITH SKIN

Oral LD50 rat 25 — 200 mg/kg: R25 TOXIC IF SWALLOWED

(iii) Subacute toxicity with oral no effect level <1 mg/kg/day or equivalent dosage by other routes.

(iv) Corrosive: R34 CAUSES BURNS, R35 CAUSES SEVERE BURNS

(v) Extreme skin or eye irritants: R41 RISK OF SERIOUS DAMAGE TO EYES.

(vi) Proven animal carcinogen or materials with suspected carcinogen activity but unknown potency: (R45) MAY CAUSE CANCER, (R49) MAY CAUSE CANCER BY INHALATION, R40 POSSIBLE RISK OF IRREVERSIBLE EFFECTS

(vii) Substances of unknown toxicity which, after inspection of the structure or of other data are likely to be classified as H by analogy.

Medium Hazard M

A material which meets any of the following criteria but does not fall into class V or H

(i) Exposure Standards <500 ppm for vapour or <10 mg/m3 for dusts.

(ii) Is harmful following acute exposure:

LC50 rat 2.0 - 20 mg/L/4hr: R20 HARMFUL BY INHALATION

Dermal LD50 rat or rabbit 400 - 2000 mg/kg: R21 HARMFUL IN CONTACT WITH SKIN

Oral LD50 rat 200 — 2000 mg/kg: R22 HARMFUL IF SWALLOWED.

(iii) Subacute toxicity with oral no effect level of 1-50 mg/kg/day or equivalent dosage by other routes.

(iv) Skin or eye irritants: R36 IRRITATING TO EYES.

(v) Skin Sensitisers: R43 MAY CAUSE SKIN SENSITISATION BY SKIN CONTACT.

(vi) Low potency carcinogens.

Low Hazard L

A material which meets any of the following criteria but does not fall into class V, H or M

(i) Exposure Standards >500 ppm for vapour or >10 mg/m3 for dusts.

(ii) Substances which are non-harmful following acute exposure:

LC50 rat >20 mg/L/4hr

Dermal LD50 rat or rabbit >2000 mg/kg

Oral LD50 rat >2000 mg/kg.

(iii) Subacute toxicity with oral no effect level of >50 mg/kg/day or equivalent dosage by other routes.

(iv) Non-irritant material.

(v) Non-genotoxic and non-carcinogenic materials.

(vi) Materials which are not skin sensitizers.

(Chemicals known or suspected of being absorbed through the skin will have the notation SKIN in their hazard data. The absence of this notation does not guarantee that the material will not be absorbed through the skin).