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Toxicity levels of chemicals

Assessment of the Dangerous Toxic Load (DTL) for Specified Level of Toxicity (SLOT) and Significant Likelihood of Death (SLOD)

Introductions

The DTL describes the exposure conditions, in terms of airborne concentration and duration of exposure, which would produce a particular level of toxicity in the general population. One level of toxicity used by HSE in relation to the provision of land use planning (LUP) advice is termed the Specified Level of Toxicity (SLOT). HSE has defined the LUP SLOT as:

As discussed in by Turner and Fairhurst (1993), these criteria are fairly broad in scope, reflecting the fact that:

  1. there is likely to be considerable variability in the responses of different individuals affected by a major accident;
  2. there may be pockets of high and low concentrations of a toxic substance in the toxic cloud release, so that not everyone will get exactly the same degree of exposure; and
  3. the available toxicity data are not usually adequate for predicting precise dose-response effects.

Importantly, the criteria are also relatively easy for non-scientists to understand in terms of the overall health impact.

The basis of the toxicology assessment

The toxicity expressed by a given substance in the air is influenced by two factors, the concentration in the air (c) and the duration of exposure (t). A functional relationship between c and t can be developed, such that the end product of this relationship is a constant:

f(c,t) = constant

This constant is known as the Toxic Load. In HSE, the Toxic Load relating to the LUP SLOT is known as the SLOT Dangerous Toxic Load or SLOT DTL. For a number of gases the relationship between c and t is simple:

Toxic Load = c x t

This relationship is sometimes known as the Haber law. As an example, animal toxicity data for methyl isocyanate indicates that the LUP SLOT is produced by each of these c and t pairs:

t (min) 5 10 30 60 120
c (ppm) 150 78 25 12 6

In this example the constant, or SLOT DTL, is 750 ppm.min (that is 150 x 5, 25 x 30, etc.).

However, the equation c x t = constant does not apply to all substances, so the following general equation has been developed:

Toxic Load = cn.t

For methyl isocyanate, n in the cn.t relationship is 1. In the case of sulphur dioxide, n = 2 and animal toxicity data suggest that the following pairs of c and t will each produce the LUP SLOT:

t (min) 5 10 30 60 120
c (ppm) 965 682 394 279 197

Here, the constant, or SLOT DTL, is 4.6 x 106 ppm2.min (that is 9652 x 5, or 3952 x 30).

Determination of the SLOT and SLOD DTLs

How does HSE determine the c and t relationship, or DTL, which would produce the LUP SLOT for a given substance? In general, the absence of human data means that we rely heavily on animal data. If information is available concerning accidental chemical exposures to humans causing severe toxicity (comparable to the LUP SLOT), it usually lacks any quantification of the duration of exposure and associated inhalation conditions. Unfortunately the available, directly relevant animal data is also usually very limited. So, a pragmatic approach, based on the data that are most likely to be available, is adopted. This involves single exposure mortality data (usually LC50 tests over a known duration) designed to identify exposure conditions that produce mortality in 50% of a group of animals. The methodology is presented in detail in the Turner and Fairhurst (1993) paper, but some key points are noted here.

The starting point is to work from single, short-term (i.e. up to 4 hours duration) inhalation exposure studies in animals. In a real-life major accident situation, residents in the vicinity of a COMAH site might be exposed for a matter of minutes as the toxic cloud might be dispersed rapidly by wind. However, in some weather conditions, people could be exposed for a matter of hours. Looking at the SLOT criteria, it can be seen that they reflect exposure conditions just on the verge of causing a low percentage of deaths in the exposed population. Hence, we take conditions producing around 1% mortality in animals as being representative of SLOT conditions. To directly observe 1% mortality (LC1) a group size of at least 100 animals is needed, whereas group sizes of 5 or 10 rats or mice are typically used in routine toxicity tests. In deriving the DTL, the available acute toxicity data from different species is compared and the data from the most sensitive animal species is used, unless there are good grounds to consider that this would be inappropriate.

Where there are sufficient dose-response data points it might be possible to derive the 1% mortality conditions using probit analysis or estimate the values by judgement. Where insufficient data are available to do this, then we take a default approach of simply dividing the LC50 by 4. We should now have one value of t and one value of c, which when taken together represent an estimate of the exposure conditions producing the LUP SLOT.

The next step is to determine the value of n in the cnt = DTL equation. If the LC50 has been experimentally determined for several time periods, preferably within the same study, then n can be calculated using a linear regression approach. If there are no data to derive n, then n is usually taken to be 1, as a default position.

We can now insert the pair of c and t values representing one set of exposure conditions predicted to produce the LUP SLOT together with the value of n into the cnt = DTL equation. The DTL equation can be used to calculate all sets of exposure conditions that would produce the LUP SLOT.

A similar procedure can be followed to derive a toxic load equation to predict exposure conditions producing any other specified level of toxicity that may be of interest. For example a DTL relating to the mortality of 50% of an exposed population, a specified level known as the SLOD DTL, can be determined (see Franks et al 1996 for more information).

There are many limitations to the approach described above, such as difficulties extrapolating animal data to humans, lack of relevant toxicity data, the use of animal data of poor or unknown quality, frequent use of the default assumption that n in the cnt = DTL equation is equal to 1 and uncertainties about the universal applicability of the cnt concept. However, the described approach is probably the best that can be achieved with the available data and current state of scientific knowledge. HSE believes that it is important in regulatory toxicology to use consistent and transparent methodology, and this approach remains central to our DTL assessments.

Sometimes there is a need for a DTL for a substance with no acute toxicity data. One way around this problem is to base the DTL assessment on the known toxic properties of a structurally related substance- known as a read-across, or SAR approach. This is an uncertain process that requires a high level of professional judgement. Alternatively, it may be recommended that data relating to an exemplar substance be used. Exemplar substances are usually the most toxicologically potent substances among those that have previously been assessed by HSE. The exemplar should have similar physical properties (e.g. solid, liquid or gas) to the substance for which a DTL cannot be determined.

The Use of Toxicology Data in COMAH Safety Reports

When preparing Safety Reports under the COMAH Regulations, authors are required to provide estimates of the extent (i.e. hazard ranges and widths) and severity (i.e. how many people are affected, including the numbers of fatalities) of the consequences of each identified major accident hazard. For an evenly distributed population, the number of fatalities resulting from a toxic release may be approximated by estimating the number of people inside the concentration contour leading to an LD50 dose (i.e. SLOD DTL). This approximation results from the assumption that those people inside the SLOD contour who do not die (due to factors such as physiology, fitness levels, etc) will be balanced by an approximately equal number outside the SLOD contour who do die (again, due to factors such as physiology, state of health etc.)

Further, the number of people injured (serious and minor) by the release may be approximated by the number people estimated to be between the SLOD and SLOT DTL contours (i.e. the SLOT DTL contour is taken as a pragmatic limit for injuries).

When estimating the numbers of people affected, authors should bear in mind that a proportion of the population will be indoors. This will provide a degree of protection against the effects of the release as compared to being outdoors. The level of protection is related to the rate at which air and toxic material enters the building and may be measured in air changes per hour (ACH). Models exist (see Davies and Purdy, 1986) to determine the outdoor concentration required to give an indoor SLOT or SLOD DTL dose. This (usually higher) outdoor concentration effectively defines the hazard range for people inside buildings.

Key references

  1. Fairhurst S and Turner RM (1993) Toxicological assessments in relation to major hazards. Journal of Hazardous Materials 33, 215-227
  2. Davies P C and Purdy G (1986) Toxic Risk Assessments - The effect of Being Indoors. Refinement of Estimates of the Consequences of Heavy Toxic Vapour Releases. I.Chem.E. Symposium No. 1, Manchester, January 1986
  3. Franks AP, Harper PJ and Bilo M (1996) The relationship between risk of death and risk of dangerous dose for toxic substances. Journal of Hazardous Materials 51, 11-34

Table of SLOT DTL and SLOD DTL Values for Various Substances

Substance name Common synonyms or abbreviations CAS number 'n' value SLOT DTL (ppmn.min) SLOD DTL
(ppmn.min)
Acetic acid   64-19-7 1 7.5 x 104 3.0 x 105
Acetone cyanohydrin 2-hydroxy-2-methyl-propanenitrile,
2-methyllactonitrile,
2-cyano-2-propanol
75-86-5 1 1.08 x 104 2.16 x 104
Acetonitrile Cyanomethane,
Methyl cyanide
75-05-8 1 8.1 x 104 1.6 x 105
Acetyl chloride Ethanoyl chloride,
Acetic acid chloride
75-36-5 1 9900 3.96 x 104
Acrolein Acrylaldehyde,
Prop-2-enal
107-02-8 1 420 1680
Acrylamide Prop-2-enamide 79-06-1 1 1.3 x 105 5.2 x 105
Acrylonitrile 2-Propenenitrile,
Propenenitrile,
Vinyl cyanide,
Cyanoethylene
107-13-1 1 9600 2.52 x 104
Acryloyl chloride

Acrylic acid chloride,
2-Propenoyl chloride,
Propenoyl chloride

814-68-6 1 3600 14400
Adiponitrile Adipyl nitrile,
1,4-Dicyanobutane
111-69-3 1 8.1 x 104 1.6 x 105
Aldicarb   116-06-3 1 33 132
Allyl alcohol 2-Propen-1-ol 107-18-6 1 6300 2.52 x 104
Allylamine

3-Aminopropene
2-Propenylamine
2-Propene-1-amine

107-11-9 0.85 1.25 x 104 3.73 x 104
Allyl chloride 3-Chloropropene 107-05-1 1 7.8 x104 3.12 x 105
Aminopropyl triazolopyrimidone ‘Paraquat emetic’ 27277-00-5 No data
Aminopyridine 4-Pyridinamine 504-24-5 1 1.122 x 104 4.5 x 104
Ammonia   anhydrous - 7664-41-7 2 3.78 x 108 1.03 x 109
Ammonium dichromate Dichromic acid, diammonium salt,
Ammonium bichromate
7789-09-5 1 905 3619
Aniline Aminobenzene,
Phenylamine
62-53-3 1 1.16 x 104 4.66 x 104
p-Anisidine 4-Methoxyaniline 104-94-9 1 1.38 x 105 5.52 x 105
Arsenic (V) acid     No data    
Arsenic trioxide Diarsenic trioxide 1327-53-3 No data    
Arsenic pentoxide Diarsenic pentaoxide,Arsenic oxide  1303-28-2 No data    
Arsine Arsenic hydride,
Arsenic trihydride
7784-42-1 2 3706 5.9 x 104
Azoxystrobin   131860-33-8 1 2900 1.1 x 104
Benzene   71-43-2 Low acute toxicity not relevant to assessment work
Benzidine 4,4'Diaminobiphenyl 92-87-5 1 2.44 x 104 9.76 x 104
Benzoquinone Quinone 106-51-4 1 2.53 x 104 1.012 x 105
Benzyl chloride α-Chlorotoluene 100-44-7 1 2250 9000
Beryllium oxide   1304-56-9 No data
β-Naphthol 2-Naphthol 135-19-3 No data
β-Oxynaphtholic acid     No data
2,2' Bipyridyl 2,2'-Bipyridine
2,2'-Dipyridyl
366-18-7 1 102 409
4,4' Bipyridyl 4-(4'-Pyridyl)pyridine 553-26-4 1 18 80
Bis (2-Chloroethyl)amine Hydrochloride   821-48-7 1 N/a 1350
Bis (2-chloroethyl) ether 1,1'-Oxybis(2-chloro) ethane,
BCEE
111-44-4 1 3280 1.31 x104
Bis (chloromethyl) ether Oxybis(chloromethane),
BCME
542-88-1 1 420 2160
Bis (2-dimethylaminoethyl) ether 2,2'-Oxybis(N,N-dimethyl ethanamine) 3033-62-3 1 1.49 x 104 5.98 x 104
Boron trichloride   10294-34-5 1 3.8 x 104 1.5 x 105
Boron trifluoride   7637-07-2 1 2320 9600
Brodifacoum   56073-10-0 1 16 26
Bromine   7726-95-6 2 2.5 x 105 8.67 x 105
Bromochloro-5,5-dimethylhydantoin BCDMH, 1-bromo-3-chloro-5,5-dimethylhydantoin, 1-bromo-3-chloro-5,5-dimethyl-2,4-imidazolidinedione, Dantoin BCDMH-powder 32718-18-6 1 998 (1.01 x 104 mg/m3 .min) 3990 (4.03 x 104 mg/m3.min)
Bromoform Tribromomethane 75-25-2 1 9.33 x 104 3.73 x 105
Bromoxynil   1689-84-5 1 780 3119
n-Butylisocyanate   111-36-4 1 640 2550
t-Butyl mercaptan 2-Methyl-2-propanethiol 75-66-1 1 9.9 x 105 3.96 x 106
n-Butyronitrile Butanenitrile,
Butyric acid nitrile,
1-Cyanopropane,
n-Propyl cyanide
109-74-0 1 7500 1.5 x 104
Cadmium oxide   1306-19-0 1 24 96
Cadmium sulphate   10124-36-4 1 24 96
Cadmium sulphide   1306-23-6 1 240 960
+ Cadmium compounds: “A” and SLOD “A” values expressed in terms of cadmium
Captan   133-06-2 1 1080 4416
Carbendazim 2-(Methoxycarbonylamino)-benzimidazole
Carbamic acid, 1H-benzimidazol-2-yl, methyl ester
10605-21-7 1 1.16 x 105 4.62 x 105
Carbon dioxide1   124-38-9 8 1.5x1040 1.5x1041
Carbon disulphide   75-15-0 1 9.6 x 104 3.84 x 105
Carbon monoxide   630-08-0 1 4.0125 x 104 5.7 x 104
Carbon tetrachloride Tetrachloromethane 56-23-5 1 7.2 x 105 2.6 x 106
Carbosulfan   55285-14-8 1 580 2320
Chlorfenvinphos   470-90-6 1 201 804
Chlorine   7782-50-5 2 1.08 x 105 4.84 x 105
Chlorine trifluoride   7790-91-2 1.3 11630 70530
Chloroacetyl chloride   79-04-9 1 9900 3.96 x 104
2-Chloroethanol Ethylene chlorohydrin,
Ethylene glycol chlorohydrin
107-07-3 1 1920 7680
2-Chloro-4-fluoroaceto phenone 4-Fluorophenacyl chloride 456-04-2 1 360 1440
2-Chloro-4-nitroaniline     No data
3-Chloro-4-methylphenyl-isocyanate   28479-22-3 No data
4-Chlorophthalic acid   118-45-6 No data
Chloromethylmethyl ether Chloromethoxymethane,
Monochlorodimethyl ether,
Methoxymethyl chloride,
Chlorodimethyl ether,
Methyl chloromethyl ether,
Monochloromethyl methyl ether,
CMME
107-30-2 1 2940 2.31 x 104
Chloromethylethyl ether CMEE   1 2940 2.31 x 104
2-Chloro-1,4-naphthoquinone 2-chloro-1,4-naphthalenedione 1010-60-2 1 2667 1.0668 x 104
Chlorophacinone   3691-35-8 1 59 240
m-Chlorophenylisocyanate 3-Chlorophenyl isocyanate 2909-38-8 1 180 780
p-Chlorophenylisocyanate 4-Chlorophenyl isocyanate 104-12-1 1 254 1018
Chloropicrin Trichloronitromethane 76-06-2 1 590 2360
Chlorosulphonic acid   7790-94-5 1 330 1320
Chlorothalonil Tetrachloroisophthalonitrile 1897-45-6 1 486 2180
Chlorotrifluoropicoline     No data
Chlorpyrifos   2921-88-2 1 3600 1.44 x 104
Coal Tar Pitch   65996-93-2   Insufficient data Insufficient data
Cobalt   7440-48-4 No data – assess as cobalt-tungsten carbide
Cobalt-Tungsten Carbide (Co-WC) alloy     1 1365 (3330 mg/m3.min as cobalt 5453 (13330 mg/m3.min as cobalt)
Cobalt (II) nitrate.hexahydrate   10026-22-9 No data
Copper cyanides   - No data
Copper pyrithione Copper 2-pyridinethiol-1-oxide 154592-20-8 1 320 1280
Cresylic acids o-Cresol
m-Cresol
p-Cresol
mixture of o-, m- and p-cresol
95-48-7
108-39-4
106-44-5
1319-77-3
1 1200 4800
Crotonaldehyde 2-butenal,
3-methylacrolein
4170-30-3 1 3187 10474
Cryolite Trisodium hexafluoro aluminate,
Sodium aluminium fluoride,
Sodium aluminofluoride
15096-52-3 1 2.42 x 104 9.7 x 104
Cyanogen chloride Chlorine cyanide,
Chlorocyanide,
Chlorocyanogen
506-77-4 1 292 1170
Cyanuric chloride 2,4,6-trichloro-1,3,5-triazine 108-77-0 1 194 780
Cyclohexylamine Cyclohexanamine,
Aminocyclohexane,
Hexahydroxyaniline,
Aminohexahydro benzene,
Hexahydrobenzenamine
108-91-8 Low acute toxicity not relevant to assessment work
Cyfluthrin   68359-37-5 1 1330 5320
β-Cyfluthrin - liquid aerosol   68359-37-5 1 265 1077
β-Cyfluthrin - dust   68359-37-5 1 1769 7076
Cyhalothrin   68085-85-8 1 1720 6880
λ-Cyhalothrin   91465-08-6 1 65 240
Demeton-S-methyl   919-86-8 1 4200 1.68 x 104
2,2-Dibromo-3-nitrilopropion amide 2,2-Dibromo-2-cyanoacetamide,
DBNPA
10222-01-2 1 1900 7600
2,5-Dichloroaniline p-Dichloroaniline,
1-Amino-2,5-dichloro benzene,
2,5-dichlorobenzenamine
95-82-9 1 3.77 x 105 1.5 x 106
1,2-Dichloroethane Ethylene dichloride 107-06-2 1 9.0 x 104 3.6 x 105
1,3-Dichloroacetone

Bischloromethyl ketone

534-07-6 1 225 900
1,3-dichloro-5-ethyl-5-methylhydantoin DCEMH, 1,3-dichloro-5-ethyl-5-methylimidazolidine-2,4-dione 89415-87-2 1 1980 7920
2,4-Dichlorophenol
1-Hydroxy-2,4-dichloro benzene,
2,4-Dichlorohydroxy benzene
120-83-2 1 8730 3.49 x 104
Dichlorvos   62-73-7 1 1502 6008
Dicyclohexylcarbodiimide N,N'-Dicyclohexyl carbodiimide 538-75-0 1 1674 6697
N,N-Diethylaniline N,N-Diethylbenzenamine,
Diethylphenylamine,
N-Phenyldiethylamine
91-66-7 1 1.85 x 104 7.42 x 104
o,o-Diethylphosphochlorido-thioate   2524-04-1 1 1200 4800
Diethylenetriamine

2,2'-Iminodi-(ethylamine),
N-(2-Aminoethyl)-1,2-ethanediamine

111-40-0 1 2580 10320
Diethyl sulphate Sulfuric acid, diethyl ester 64-67-5 1 6.0 x 104 8.4 x 104
Difenacoum   56073-07-5 1 38 152
Diglyme bis(2-Methoxyethyl) ether,
Diethylene glycol dimethyl ether,
Dimethyl carbitol,
2,5,8-Trioxynonane,
DEGDM(E),
111-96-6 No data
Dimethoate Fosfamid 60-51-5 1 5510 2.2 x 104
N,N-Dimethylaminoethyl Acrylate   2439-35-2 1 665 2658
4-Dimethylaminopyridine   1122-58-3 1 4.2 x 104 1.68 x 105
Dimethylaminosulphonyl Chloride     3 7.54 x 105 4.83 x 107
N,N-Dimethylaniline
(Dimethylamino)benzene,
N,N-Dimethylamino benzene,
Dimethylaniline,
Dimethylphenylamine,
N,N-Dimethylphenyl amine
121-69-7 1 1.19 x 104 No Data
Dimethylcarbamoyl chloride DMCC 79-44-7 1 1.62 x 104 6.48 x 104
Dimethylnitrosamine N-Nitrosodimethylamine,
DMN
62-75-9 1 1940 3840
o,o-Dimethylphosphochlorido-thioate   2524-03-0 1 1500 6000
Dimethyl sulphate   77-78-1 1 250 1000
Dimethyl sulphide Methyl sulphide, 75-18-3 1 6.72 x 106 9.6 x 106
2,4 Dinitrochlorobenzene 1-Chloro 2,4-dinitro benzene
DNCB
97-00-7 1 1.11 x 105 4.44 x 105
2,4-Dinitrotoluene 1-Methyl-2,4-dinitrobenzene, 2,4-dinitrotoluol 121-14-2 1 2842 1.1368x104
Diphenylmethane 4,4' - diisocyanate Methylene bisphenyl isocyanate
MDI
monomeric MDI
101-68-8 1 (monomeric) 1030 (monomeric) 4080 (monomeric)
polymeric (trifunctional) MDI   1 (polymeric) 1100 (polymeric) 4400 (polymeric)
Diquat dibromide Diquat
1,1'-Ethylene-2,2'bipyridylium
85-00-7 1 347 1389
Disulfoton   298-04-4 1 186 615
Endosulphan   115-29-7 1 284 1134
Epichlorohydrin 1-Chloro-2,3-epoxy propane 106-89-8 1 1.04 x 105 1.30 x 105
2-Ethylhexyl nitrate

2-Ethylhexyl ester;
3-Nitroxymethyl-heptane

27247-96-7 No data
Ethyl chloroformate   541-41-3 1 2160 8700
Ethyl mercaptan Ethanethiol 75-08-1 1 1.66 x 105 6.62 x 105
Ethylene dibromide Dibromoethane,
EDB
106-93-4 1 1.6 x 104 4.44 x 104
Ethylene oxide Oxirane 75-21-8 1 4.68 x 104 1.872 x 105
Ethyleneimine Aziridine 151-56-4 1 1155 8250
Fluoroacetic acid and salts (including Ethyl fluoroacetate)   144-49-0 1 460 1840
Fluorine   7782-41-4 2 3.8 x 105 1.5 x 106
Flutriafol   76674-21-0 1 7.96 x 104 3.18 x 105
Formaldehyde   50-00-0 1 5700 8100
Formurea Urea Formaldehyde - No data
Furfural Furfuraldehyde,
2-Furaldehyde,
Fural,
2-Furancarboxaldehyde,
2-Formylfuran,
2-Furyl-methanal
98-01-1 1 1.56 x 104 6.22 x 104
Glutaraldehyde Glutaral,
1,5-Pentanedial
111-30-8 1 1410 5640
Heptenophos   23560-59-0 1 8060 3.22 x 104
bis-Hexamethylenetriamine     No Data –
Hexan-2-one Butylmethylketone,
Methyl butyl ketone,
MBK
591-78-6 1 4.8 x 105 1.92 x 106
Hydrazine Diamine 302-01-2 1 1.51 x 104 6.05 x 104
Hydrogen bromide   10035-10-6 1 1.22 x 104 4.88 x 104
Hydrogen chloride   7647-01-0 1 2.37 x 104 7.65 x 104
Hydrogen cyanide Hydrocyanic acid 74-90-8 2 1.92 x 105 4.32 x 105
Hydrogen fluoride   7664-39-3 1 1.2 x 104 2.1 x 104
Hydrogen peroxide
(solution)
  7722-84-1 1 8.6 x 104 3.44 x 105
Hydrogen selenide   7783-07-5 1 111 427
Hydrogen sulphide   7783-06-4 4 2x1012 1.5x1013
Iodine   7553-56-2 1 2055 8220
Iodomethane Methyl iodide 74-88-4 1 1.29 x 104 5.17 x 104
Ioxynil 3,5-Diiodo-4-hydroxybenzonitrile 1689-83-4 1 4250 1.7 x 104
Isopropylphenylisocyanate 4-Isopropylphenylisocyanate 31027-31-3 No Data
Lindane γ-1,2,3,4,5,6-Hexachloro cyclohexane,
γ-BHC
58-89-9 1 2650 1.06 x 104
Methanesulfonyl chloride Methylsulfonyl chloride,
Mesyl chloride,
Methanesulfonic acid chloride
124-63-0 1 5750 2.3 x 104
Methanol   67-56-1 1 8.02 x 105 2.67 x 106
Methyl bromide Bromomethane 74-83-9 1 3.0 x 104 4.8 x 104
Methyl chloride Chloromethane 74-87-3 1 2.02 x 105 8.1 x 105
Methyl chloroformate   79-22-1 1 1320 5280
Methylchloroisothiazolinone 5-chloro-2-methyl-4-isothiazolin-3-one,
5-chloro-2-methyl-3-isothiazolone
(component of Kathon CG mix)
26172-55-4 1 1660 6650
Methylene bis(thiocyanate) Methylene dithiocyanate,
Thiocyanic acid, methylene ester
6317-18-6 1 86 346
Methyl isocyanate Isocyanic acid, methyl ester,
Methyl carbylamine
624-83-9 1 750 1680
N-Methylolacrylamide
N-Methanolacrylamide,
Monomethylolacrylamide,
N-(Hydroxymethyl)-2- propenamide
924-42-5 1 8.64 x 104 3.5 x 105
3-Methyl phenylisocyanate m-Tolyl isocyanate 621-29-4 1 360 1440
4-Methyl-3-thiosemicarbazide   6610-29-3 1 4400 1.76 x 104
Methyl vinyl bromide     1 3.4 x 106 1.4 x 107
Monochloroacetic acid Chloroacetic acid 79-11-8 1 2730 1.0938 x 104
Monochloroacetonitrile Chloroacetonitrile 107-14-2 1 6.0 x 104 8.4 x 104
1,4-Naphthoquinone α-Naphthoquinone,
1,4-Naphthalenedione
130-15-4 1 414 1656
2-Naphthylamine β-Naphthylamine 91-59-8 1 1.068 x 105 4.27 x 105
Nickel carbonyl Nickel tetracarbonyl,
Tetracarbonyl nickel
13463-39-3 1 150 450
Nickel dioxide   12035-36-8 No data – assess as Nickel subsulphide
Nickel monoxide Nickelous oxide, Nickel (II) oxide, Mononickel oxide 1313-99-1 No data – assess as Nickel subsulphide
Nickel (II) nitrate.hexahydrate   13478-00-7 No data
Nickel sulphide Nickelous sulphide, Nickel (II) sulphide 16812-54-7 No data – assess as Nickel subsulphide
Nickel trioxide Dinickel trioxide, Nickel sesquioxide 1314-06-3 No data – assess as Nickel subsulphide
Nicotine 3-[(2S)-1-Methyl-2-pyrrolidinyl]pyridine 54-11-5 1 18.5 3382
Nitric oxide   10102-43-9 1 2.09 x 104 2.43 x 104
Nitroaniline-p-sulphonic acid   82324-60-5 No Data
Nitrobenzene Nitrobenzol 98-95-3 1 8.54 x 104 3.41 x 105
o-Nitrochlorobenzene Chloro-o-nitrobenzene,
2-Chloro-1-nitrobenzene,
2-CNB
85-73-3 1 1.8 x 104 7.2 x 104
p-Nitrochlorobenzene p-Chloronitrobenzene,
1-Chloro-4-nitrobenzene,
PCNB
100-00-5 1 5.61 x 104 2.24 x 105
Nitrogen dioxide Dinitrogen tetraoxide 10102-44-0 2 9.6 x 104 6.24 x 105
Nitroglycerine Glycerol trinitrate 55-63-0 1 1700 6800
m-Nitrotoluene m-Methylnitrobenzene 99-08-1 1 5.06 x 104 2.02 x 105
o-Nitrotoluene o-Methylnitrobenzene 88-72-2 1 1.38 x 105 5.52 x 105
p-Nitrotoluene para-Aminonitrobenzene,
Nitroaniline,
4-Nitrobenzenamine,
p-Nitrophenylamine
99-99-0 1 1.89 x 105 7.56 x 105
2-Octyl-(2H)-isothiazol-3-one   26530-20-1 1 1570 1.59 x 104
Ozone   10028-15-6 1 1980 3600
Paraquat dichloride 1,1'-Dimethyl-4,4'-bipyridinium dichloride,
Methyl viologen dichloride
1910-42-5 1 8.6 34.2
Pentachloroethane
Ethane pentachloride,
Pentalin
76-01-7 1 1.27 x 105 5.09 x 105
Peracetic acid   79-21-0 1 2488 9951
Perfluoroisobutene perfluoroisobutylene,
octafluoroisobutylene,
1,1,3,3,3-pentafluoro-2-trifluoro-methyl-1-propene
383-21-8 1 54 124
Phenol Benzenol,
Carbolic acid,
Hydroxybenzene,
Oxybenzene,
Phenic acid,
Phenylic acid,
Phenyl hydrate,
Phenyl hydroxide,
Phenylic alcohol
108-95-2 1 1.5 x 104 6.0 x 104
Phenol-sulphonic acid     No data - Use Data for Sulphuric Acid Mist
Phenolsulphonic acid     2 1.3 x 104 2.08 x 105
Phenyl dichlorophosphate   770-12-7 No Data
Phenylisocyanate   103-71-9 1 180 780
Phorate   298-02-2 1 15 60
Phosgene Carbonyl chloride 75-44-5 1 108 348
Phosphine Hydrogen phosphide,
Phosphorus hydride,
Phosphorus trihydride,
7803-51-2 1 6900 1.08 x 104
Phosphorus oxychloride Phosphoryl chloride 10025-87-3 1 2880 1.152 x 104
Phosphorus trichloride Phosphorus(III) chloride,
Phosphorus chloride
7719-12-2 1 3048 1.2192 x 104
Phosphorus pentoxide Phosphoric anhydride 1314-56-3 1 600 2400
Phthallic anhydride   85-44-9 No Data
4-Picoline 4-Methyl pyridine 108-89-4 1 1.416 x 105 5.66 x 105
Piperidine   110-89-4 1 5.08 x 104 2.03 x 105
Pirimicarb   23103-98-2 1 8830 3.53 x 104
Pirimiphos Ethyl   23505-41-1 1 1580 6320
Potassium chromate Dipotassium monochromate 7789-00-6 1 922 3689
Potassium dichromate Potassium bichromate 7778-50-9 1 461 1845
Potassium hydroxide Caustic potash,
Lye,
Potassium hydrate
1310-58-3 No Data
Potassium nitrate Saltpeter,
Niter,
Nitric acid, potassium salt
7757-79-1 1 3.8 x 105 1.5 x 106
Potassium oxide Potassium (I) oxide,
Dipotassium oxide
12136-45-7 1 5377 2.15 x 104
Propionitrile Ethyl cyanide,
Propanenitrile,
2-Methylacetonitrile
107-12-0 1 4900 9800
Propyl chloroformate

Propyl chlorocarbonate;
Formic acid, chloro-,
propyl ester;
Carbonochloridic acid,
propyl ester

109-61-5 1 6150 24600
Propylene oxide 1,2-Epoxypropane,
Methyloxirane
75-56-9 1 5.16 x 104 2.04 x 105
Pyridine   110-86-1 1 1.35 x 105 5.4 x 105
Selenium dioxide Selenium(IV) oxide 7446-08-4 1 3120 No Data
Selenium (dust)   7782-49-2 1 1460 7303
Silicon tetrachloride Tetrachlorosilane 10026-04-7 1 4.8 x 105 1.9 x 106
Sodium chloroacetate Sodium salt of chloroacetic acid 3926-62-3 1 2230 8918
Sodium chromate Chromic acid, disodium salt, 7775-11-3 1 926 3705
Sodium cyanide   143-33-9 2 1.92 x 105 4.32 x 105
Sodium cyanide   143-33-9 No data - Assess as HCN
Sodium dichromate anhydride Dichromic acid, disodium salt
Sodium bichromate
10588-01-9 1 683 2732
Sodium fluoroacetate Sodium fluoroacetic acid,

Fluoroacetic acid, sodium salt
62-74-8 1 46 185
Sodium hydrogen sulphide Sodium bisulphide,
Sodium hydrosulphide
16721-80-5   No data No data
Sodium hydroxide   1310-73-2 No Data
Sodium methoxide Sodium methanolate 124-41-4 No Data - Assess as Methanol
Sodium methoxide Sodium methanolate 124-41-4 1 8.02 x 105 2.67 x 107
Sodium nitrite Nitrous acid, sodium salt 7632-00-0 1 4.38 x 104 1.75 x 105
Sodium oxide
Sodium (I) oxide,
Disodium oxide
1313-59-3 1 8152 3.4 x 104
Sodium selenite   10102-18-8 1 209 840
Sulphur monochloride and
Sulphur dichloride
Disulphur dichloride
Sulphur (II) chloride
Sulphur chloride
10025-67-9
10545-99-0
1 2.7 x 104 1.08 x 105
Sulphur dioxide   7446-09-5 2 4.655 x106 7.448 x 107
Sulphuric acid mist Sulphur Trioxide 7664-93-9 2 1.3 x 104 2.08 x 105
Sulphuryl difluoride Sulphuryl fluoride,
Sulfuryl fluoride,
Sulfuric oxyfluoride,
Vikane
2699-79-8 1 1.78 x 104 7.09 x 104
Tefluthrin   79538-32-2 1 1100 4400
Terbufos   13071-79-9 1 117 470
Tetraethyl Lead TEL 78-00-2 1 1520 3790
1,1,2,2-Tetrachloroethane

Acetylene tetrachloride;
sym-Tetrachloro ethane;
1,1-Dichloro-2-2,
dichloroethane

79-34-5 1 7.37 x 104 2.95 x 105
Tetramethyl Lead TML 75-74-1 1 4.79 x 104 1.2 x 105
Tetramethylammonium hydroxide TMAH,
Ammonium hydroxide,
tetramethyl
75-59-2 No data
2-[(Thiocyanatomethyl)-thio]-benzothiazole     1 340 1350
Thioglycolic acid Mercaptoacetate,
Mercaptoacetic acid,
Thiovanic acid,
α-Mercaptoacetic acid,
2-Mercaptoacetic acid
68-11-1 1 3280 1.31 x 104
Thionyl chloride

Sulfinyl chloride,
Sulphur chloride oxide,
Sulphur oxychloride,
Sulphurous dichloride,
Sulphurous oxychloride,
Thionyl dichloride

7719-09-7 1 13320 44160
Thiophosgene Carbon chlorosulfide 463-71-8 No Data
Titanium tetrachloride Titanium chloride, tetrachlorotitanium 7550-45-0 1 3345 13380
Toluene diisocyanate Toluene-2,4-diisocyanate,
TDI
584-84-9 1 176 480
Trinickel disulphide Nickel subsulphide 12035-72-2 1 83.5 334
Tungsten hexafluoride P - 7783-82-6 1 2400 9600
2,4,5 Trichloroaniline   636-30-6 No Data
3,5,3 Trichlorobenzidine     No Data
Vinyl bromide Bromoethylene,
Bromoethene,
Monobromooethylene,
Ethylene monobromide,
Monobromoethene,
VB
593-60-2 1 3.75 x 105 1.5 x 106
Vinyl chloride Chloroethylene,
Chloroethene,
Monochloroethylene,
Ethylene monochloride,
Monochloroethene,
VC, VCM,
75-01-4 1 3.39 x 106 1.36 x 107
Warfarin   81-81-2 1 103 6000
2,4 (isomer) Xylidenes



2,6-xylidine
2,4-Dimethylaniline,
2,4-Dimethylamino benzene,
1-Amino- 2,4-dimethylbenzene,
2,6-Dimethylaniline,
2,6-Dimethylamino benzene,
1-amino- 2,6-dimethyl benzene
95-68-1



87-62-7
1 1.554 x 104 6.3 x 104

P Provisional value. Please refer to HSE for further details.

1 Data available for carbon dioxide indicate that it does not meet the criteria for classification as a dangerous substance.

Updated 2015-10-28