Update on the Human Health Assessment of Long-Chain 

Chlorinated Alkanes 

Health Canada 

May 2012 
ii

SYNOPSIS 

Chlorinated paraffins (CPs) were included in 1989 on the Priority Substances List under 

the 1988 Canadian Environmental Protection Act (CEPA 1988) for assessment of 

potential risks to the environment and human health. 

The use of the term paraffins to identify these substances was recently changed to alkanes 

to harmonize with more current nomenclature that is recognized by other jurisdictions 

and international bodies. 

CPs are chlorinated alkanes that have carbon chain lengths ranging from 10 to 38 with 

varying degree of chlorination. They are subdivided into three groups: short-chain 

chlorinated paraffins with 10-13 carbon atoms (SCCPs), medium-chain chlorinated 

paraffins with 14-17 carbon atoms (MCCPs) and long-chain chlorinated paraffins with 18 

to 38 carbon atoms (LCCPs). 

In 1993, Environment Canada and Health Canada published an assessment report that 

concluded SCCPs constitute or may constitute a danger to human health or life according 

to the criteria described in the CEPA 1988. However, available data at that time were 

considered insufficient to conclude whether short-, medium- or long-chain chlorinated 

paraffins were harmful to the environment or whether medium- or long-chain chlorinated 

paraffins were considered a danger to human health. 

After addressing the critical data gaps identified in the 1993 assessment report, a draft 

follow-up report was published in 2005, which was followed by a 60-day comment 

period. The final follow-up report was published in 2008 with the conclusion that all CPs 

are harmful to human health under paragraph 64(c) of CEPA 1999 and CPs containing up 

to 20 carbon atoms are harmful to environment under paragraph 64(a) of CEPA 1999. 

In 2009, the Environment Agency of United Kingdom published an environmental risk 

assessment report on LCCPs and this new information informed an update to the 

exposure characterization for various human subpopulations for LCCPs. 

There were no new critical health effects identified for LCCPs. Therefore, the tolerable 

daily intake (TDI) (i.e., the level of intake to which it is believed that a person may be 

exposed daily over a lifetime without deleterious effects) of 71 μg/kg-bw per day, 

derived for non-neoplastic effects in the follow-up assessment in 2008, was used for risk 

characterization. 

Upper-bounding estimates of daily intakes of LCCPs by the general population of Canada 

are well below the established TDI, and therefore, it is concluded that long-chain 

chlorinated alkanes that have the molecular formula CnHxCl(2n+2-x) in which 18 ≤ n ≤ 38 

are not harmful to human health as defined in paragraph 64(c) of CEPA 1999. 
INTRODUCTION 

Chlorinated paraffins (CPs) are chlorinated alkanes that have carbon chain lengths 

ranging from 10 to 38. They are subdivided into three groups: short-chain chlorinated 

paraffins with 10-13 carbon atoms (SCCP), medium-chain chlorinated paraffins with 14-

17 carbon atoms (MCCP) and long-chain chlorinated paraffins with 18 to 38 carbon 

atoms (LCCP). 

CPs were included in 1989 on the Priority Substances List under the 1988 Canadian 

Environmental Protection Act (CEPA 1988) for assessment of potential risks to the 

environment and human health. In 1993, Environment Canada and Health Canada 

published an assessment report that concluded that SCCPs constitute or may constitute a 

danger to human health or life according to the criteria described in the CEPA. However, 

available data at that time were considered insufficient to conclude whether short-, 

medium- or long-chain chlorinated paraffins were harmful to the environment or whether 

medium- or long-chain chlorinated paraffins were considered a danger to human health. 

Following the publication of the assessment report, research to address data gaps relevant 

to the assessment of impacts of CPs on the environment was undertaken. Furthermore, an 

industry survey on the manufacture, import and uses of CPs in Canada was conducted for 

the years 2000 and 2001 through a Canada Gazette Notice issued pursuant to section 71 

of CEPA 1999. Finally, the scientific literature was reviewed to identify new exposure 

and toxicological data. 

On June 11, 2005, the Ministers of the Environment and of Health published the 

summary of the scientific results of the follow-up assessment on CPs in the Canada 

Gazette, Part I for a 60-day public comment period. At the same time, a statement 

outlining the proposed risk management measure - a prohibition regulation - was also 

published. Comments were subsequently received from industry and industry 

associations. The draft follow-up assessment report was revised based on these comments 

and the final was published on August 30, 2008. The final follow-up assessment report 

concluded that CPs containing between 10 and 38 carbon atoms are harmful to human 

health under paragraph 64(c) of CEPA 1999 and CPs containing up to 20 carbon atoms 

are harmful to the environment under paragraph 64(a) of CEPA 1999. 

In 2011, Health Canada made a decision to update the human health assessment of 

LCCPs based on new information relevant to exposure characterization for the general 

population in Canada. 

This Update on the Human Health Assessment of Long-Chain Chlorinated Alkanes, 

which was built upon the final follow-up assessment report published in 2008, was 

prepared by staff in the Existing Substances Program at Health Canada and incorporates 

input from other programs within the department. The external peer review of exposure 

assessment was conducted by WECC Wania Environmental Chemists Corp., Toronto, 

Canada. The draft Update on the Human Health Assessment of Long-Chain Chlorinated 

Alkanes that was published in September 2011 was subject to a 60-day public comment 

1
period. Although external comments were taken into consideration, the final content and 

outcome of this assessment report remain the responsibility of Health Canada. 

SUMMARY OF INFORMATION CRITICAL TO THE ASSESSMENT UNDER 

CEPA 1999 

In the 2008 follow-up assessment, upper-bounding intake estimates for long-chain 

chlorinated paraffins (LCCPs) were calculated using concentrations in a limited number 

of foodstuffs in the United Kingdom (Campbell and McConnell 1980). Furthermore, 

concentrations in foods were represented by the limits of detection for five of eight food 

groups in the calculation of daily intake. The confidence in exposure was low because of 

high uncertainty in estimating total daily intakes of LCCPs from drinking water, food and 

soil. For the general population, none of those intakes exceeded the TDI (71 μg/kg 

bw/day). However, for infants, non-formula fed, the total daily intake of LCCPs of 16 

μg/kg bw/day was within the same order of magnitude. It was on this basis that LCCPs 

were concluded to be harmful to human health as defined in paragraph 64(c) of the 

Canadian Environmental Protection Act, 1999 (CEPA 1999). 

 

Since then, in 2009, the United Kingdom Environment Agency published an 

environmental risk assessment report on LCCPs (Environment Agency 2009). In the 

absence of monitoring data, environmental concentrations of three main types of LCCPs, 

C18-20 liquid, C>20 liquid and C>20 solid, were predicted using European Union System for 

the Evaluation of Substances (EUSES) modelling based on physical chemical properties. 

Furthermore, EU release volume for the selective types of LCCPs was used as no UK 

release data was identified. 

Health Canada has updated its assessment of LCCPs, informed by the United Kingdom 

Environment Agency report. As there is no Canadian release data for LCCPs, an EU 

release value of 140,000 kg/year is used in the prediction. This value is considered 

conservative as chlorinated paraffins are no longer produced in Canada. Use volume in 

Canada in 2001 was approximately 200,000 kg with no reportable releases identified to 

the National Pollutants Release Inventory (NPRI) as of 2009 (NPRI 2009). Exposure 

estimates from the environment and food for C18-20 andC>20 liquid LCCPs are estimated 

using a Farfield Human Exposure model (FHX 2008). Analytical methods currently 

available for LCCPs do not routinely differentiate the types of chlorinated paraffins either 

in terms of chlorine content or chain length distribution. The FHX model, developed by 

the Centre for Environmental Modelling and Chemistry of Trent University for Health 

Canada, brings together information on chemical partitioning, degradation, 

environmental fate and transport and food web bioaccumulation for assessing human ageclass-specific exposure from chemicals released to the environment. The FHX model 

calculates steady-state concentrations in the multi-media compartments such as air, water 

and soil and various food groups, including fruits, vegetables, milk, dairy, fish, and meats 

based on the unit emission rate. The EPIsuite v.4.0 predicted physical chemical 

properties (MW, VP, water solubility, log Kow and half-lives in air, water, soil and 

sediment, in fish ) (EPIsuite 2008) for C18H37Cl1 (CAS 106232-85-3), C18H22Cl16 and 

2
C18H30Cl8 of the C18-20 alkanes group and C22H45Cl1 (CAS 85535-86-0) of the C>20 alkane 

group were used in the FHX model (Appendix 1). 

There were no new critical health effects identified for LCCPs. Therefore, the tolerable 

daily intake (TDI) (i.e., the level of intake to which it is believed that a person may be 

exposed daily over a lifetime without deleterious effects) of 71 μg/kg-bw per day, 

derived for non-neoplastic effects in the follow-up assessment in 2008 was used for risk 

characterization. This TDI value was based on the lowest dose of LCCP (LowestObserved-Adverse-Effect Level [LOAEL] = 100 mg/kg-bw per day) at which adverse 

effects (diffuse lymphohistiocytic inflammation in the liver and in the pancreatic and 

mesenteric lymph nodes in female rats) were observed, in a carcinogenicity bioassay in 

which an adequate range of endpoints had been examined (NTP, 1986; Bucher et al., 

1987), divided by an uncertainty factor of 1000 (×10 for intraspecies variation; ×10 for 

interspecies variation; ×10 for use of a LOAEL rather than a NOAEL) and multiplied by 

5/7 (for conversion of 5 days/week administration to daily exposure) (Health Canada, 

2008). 

Intake of C18H37Cl1 with its upper bounding intake estimates ranging from 0.007 μg per 

kg-bw per day for 60+ age group to 0.024 μg per kg-bw per day for 0.5-4 years age 

group, is the highest among the three substances within C18-20 alkanes group. These intake 

estimates are 10000 and 3000 times lower, respectively, than the tolerable daily intake of 

71 μg per kg-bw per day (Appendix 2). The intake estimates for the other two 

representative substances in the C18-20 substances, C18H22Cl16 and C18H30Cl8, were found 

at an order of magnitude lower than C18H37Cl1. This could possibly be due to the higher 

vapour pressure and water solubility of the latter substance. The estimated upper bound 

intakes of the C>20 type is predicted to range from 0.013 μg per kg-bw per day for 60+ 

age group to 0.040 μg per kg-bw per day for 0.5-4 years age group, which are 5500 and 

1800 times lower, respectively, than the tolerable daily intake. 

As these estimates are well below than the derived TDI, it is concluded that LCCPs are 

not harmful to human health as defined in paragraph 64(c) of the Canadian 

Environmental Protection Act, 1999. 

Uncertainties in Evaluation of Risk to Human Health 

There is high degree of confidence in the database of toxicological studies upon which 

the TDI for LCCPs is based as the database is complete, including a well documented 

carcinogenicity bioassay in rat and mice. 

The commercial products in the C18-20 and C>20 liquid groups contain a mixture of many 

components with different carbon chain length and various chlorine weight content which 

can range from a low of 20% to a high of 70%. The upper bounding exposure estimates 

of C18-20 and C>20 LCCPs are based on the predicted physical chemical properties of the 

specific C18-20 and C>20 liquid compounds with different chlorine content. There is 

considerable uncertainty over the physical chemical properties chosen for the 

environmental modelling and the bioconcentration factor used to estimate the uptake 

3
from soil into root crops, from air into leaf crops and the subsequent transfer into the food 

chain. However, given the very conservative input values of the predicted physical 

chemical, confidence is high that estimated exposure to LCCPs from the environment and 

food for different age class of the general population are considerably lower than the TDI 

of 71 μg/kg bw/day. 

CONCLUSION 

Based on the information presented, it is concluded that LCCPs (i.e., chlorinated 

paraffins with 18 to 38 carbon atoms) are not entering the environment in a quantity or 

concentration or under conditions that may constitute a danger to human life or health as 

defined in the paragraph 64(c) of CEPA 1999. 

4
References 

Bucher, J.R., R.H. Alison, C.A. Montgomery, J. Huff, J.K. Haseman, D. Farnell, R. Thompson and J.D. 

Prejean. 1987. Comparative toxicity and carcinogenicity of two chlorinated paraffins in F344/N rats and 

B6C3F1 mice. Fundam. Appl. Toxicol. 9: 454–468. 

Campbell, I. and G. McConnell. 1980. Chlorinated paraffins and the environment. 1. Environmental 

occurrence. Environ. Sci. Technol. 14(10): 1209–1214. 

Canada 1993. Priority Substances List Assessment Report – Chlorinated Paraffins 

Canada, Dept. of the Environment. 2005. Canadian Environmental Protection Act, 1999: Notice with 

respect to chlorinated paraffins. Canada Gazette. Part 1, Vol. 139 No. 24, pg 2046-2050. Available at: 

http://gazette.gc.ca/archives/p1/2005/index-eng.html 

Environment Agency UK. 2009. Environmental risk assessment: long chain chlorinated paraffins science 

report – Environment Agency, UK. Jan. 2009 

[EPIsuite] Estimation Programs Interface Suite for Microsoft Windows [Estimation Model]. 2008. Version 

4.00. Washington (DC): U.S. Environmental Protection Agency, Office of Pollution Prevention and Toxics; 

Syracuse (NY): Syracuse Research Corporation. Available from: 

www.epa.gov/oppt/exposure/pubs/episuite.htm 

FHX 2008 Farfield Human Exposure. The Canadian Centre for Environment Modelling 

Trent University 

Health Canada. 1998. Exposure factors for assessing total daily intake of priority substances by the general 

population of Canada. Unpublished report. Ottawa (ON): Health Canada, Environmental Health 

Directorate. 

Health Canada, 2008. Follow-up report on PSL1 substance for which there was insufficient information to 

conclude whether the substance constitutes a danger to the environment and to the Human Health. 

IRDC (International Research and Development Corporation). 1981. Teratology Study in Rabbits With 

Chlorinated Paraffin: 43% Chlorination of Long Chain Length n-paraffin, Studies conducted for the 

Working Party of the Chlorinated Paraffin Manufacturers Toxicology Testing Consortium, Report Number 

438-030. 

IRDC (International Research and Development Corporation). 1982. Teratology Study in Rabbits With 

Chlorinated Paraffin: 70% Chlorination of Long Chain Length n-paraffin, Studies conducted for the 

Working Party of the Chlorinated Paraffin Manufacturers Toxicology Testing Consortium, Report Number 

438-039. 

IRDC (International Research and Development Corporation). 1983a. Teratology Study in Rats With 

Chlorinated Paraffin: 43% Chlorination of Long Chain Length n-paraffin, Studies conducted for the 

Working Party of the Chlorinated Paraffin Manufacturers Toxicology Testing Consortium, Report Number 

438-015. 

IRDC (International Research and Development Corporation). 1983b. Teratology Study in Rats With 

Chlorinated Paraffin: 70% Chlorination of Long Chain Length n-paraffin, Studies conducted for the 

Working Party of the Chlorinated Paraffin Manufacturers Toxicology Testing Consortium, Report Number 

438-045. 

[NPRI] National Pollutant Release Inventory. 2009. Gatineau (QC): Environment Canada Available from: 

HThttp://www.ec.gc.ca/pdb/querysite/query_e.cfm 

5
NTP (National Toxicology Program). 1986. NTP technical report on the toxicology and carcinogenesis 

studies of chlorinated paraffins (C23, 43% chlorine) (CAS No. 63449-39-8) in F344/N rats and B6C3F1 

mice (gavage studies). National Institutes of Health, Research Triangle Park, North Carolina (NTP TR 305; 

NIH Publication No. 86-2561). 

Serrone, D.M., R.D.N. Birtley, W. Weigand, and R. Millischer. 1987. Toxicology of Chlorinated Paraffins. 

Food Chem. Toxicol., 25(7):553-562. 

6
Appendix 1: Predicted physical/chemical properties of the C18-20 and C>20 alkane 

group 

Parameter C18H37Cl1 

C18-20 alkanes 

group 

C18H22Cl16 

C18-20 alkanes 

group 

C18H30Cl8 

C18-20 alkanes 

group 

C22H45Cl1

C>20 alkane 

group 

Molecular Weight 288.95 530.06 805.6 345.06 

Vapour Pressure 

(Pa) 

3.79E-01 3.32E-06 6.43E-11 9.7E-04 

Solubility (g/m3) 1.4E-04 3.87E-07 3.39E-10 1.4E-06 

Log Kow 9.36 10.6 12.07 11.2 

Half-life in air 

(day) 

0.51 0.94 5.45 0.41 

Half-life in water 

(days) 

38 180 180 15 

Half-life in soil 

(days) 

75 360 360 30 

Half-life in 

sediment (days) 

337 1620 1620 135 

Metabolic half-life 

in fish (days)1 

143 811 6440 495 

Metalic half-life in 

avian and 

mammals (days) 

143 811 6440 495 

1 Calculated from first order rate constant value for 1 kg fish -BCFBAF (EPISuite 2008) 

7
8

Appendix 2: Predicted upper-bounding daily intakes of C18H37Cl1 for the general 

population in Canada 

Estimated intake (μg/kg-bw per day) of C18-20 LCCPs by various age 

groups 

0–6 months1, 2,

Route of 

exposure 

formula 

fed 

not 

formula 

fed 

0.5–4 

years3

5–11 

years4

12–19 

years5

20–59 

years6

60+ 

years7

Ambient 

air 

1.92x10-6 4.12x10-6 3.21x10-6 1.83x10-6 1.57x10-6 1.36x10-6

Indoor air 1.35x10-5 2.88x10-5 2.25x10-5 1.28x10-5 1.10x10-5 9.54x10-6

Drinking 

water 

8.49x10-8. 9.58x10-8 7.53x10-8 4.29x10-8 4.49x10-8 4.72x10-8

Food and 

beverages8

2.26x10-7

0.018 0.024 0.017 0.010 0.009 0.007

Soil NA NA NA NA NA NA

Total intake <0.01 0.018 0.024 0.017 0.010 0.009 0.007

Abbreviation: NA, not available. 

1

 Assumed to weigh 7.5 kg, to breathe 2.1 m3 of air per day, to drink 0.8 L of water per day (formula 

fed) or 0.3 L/day (not formula fed) and to ingest 30 mg of soil per day (Health Canada 1998). Formulafed infants are assumed to consume no other foods. 2

 For exclusively formula-fed infants, intake from water is synonymous with intake from food. The 

concentration of LCCPs in water used to reconstitute formula was based on predicted water 

concentration. data.. Approximately 50% of infants are introduced to solid foods by 4 months of age 

and 90% by 6 months of age (NHW 1990). 3

 Assumed to weigh 15.5 kg, to breathe 9.3 m3 of air per day, to drink 0.7 L of water per day and to 

ingest 100 mg of soil per day (Health Canada 1998). 4

 Assumed to weigh 31.0 kg, to breathe 14.5 m3 of air per day, to drink 1.1 L of water per day and to 

ingest 65 mg of soil per day (Health Canada 1998). 5

 Assumed to weigh 59.4 kg, to breathe 15.8 m3 of air per day, to drink 1.2 L of water per day and to 

ingest 30 mg of soil per day (Health Canada 1998). 6

 Assumed to weigh 70.9 kg, to breathe 16.2 m3 of air per day, to drink 1.5 L of water per day and to 

ingest 30 mg of soil per day (Health Canada 1998). 7

 Assumed to weigh 72.0 kg, to breathe 14.3 m3 of air per day, to drink 1.6 L of water per day and to 

ingest 30 mg of soil per day (Health Canada 1998). 8 The food group includes fruits, vegetables, dairy, fish and meats based on mechanistic mass 

bioaccumulation models that include biotransformation loss