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SIDS INITIAL ASSESSMENT PROFILE

CAS Numbers

and

Chemical Names

63449-39-8 Paraffin waxes and hydrocarbon waxes, chloro

85535-86-0 Alkanes, C18 - 28, chloro

85422-92-0 Paraffin oils, chloro

 

Example

Structural Formulae

CnH2n+2-yCly, where n = 18 to 30 and y = ~4 to ~30

SUMMARY CONCLUSIONS OF THE SIAR

Analogue/Category Justification

The Long-Chain Chlorinated Paraffins (LCCP) category contains complex commercial substances whose chemical 

components are predominantly in the range of carbon chain lengths from C18 to C30 with chlorine content in the range of 

approximately 35-72% by weight. Chlorinated paraffins (CP) are derived from the chlorination of straight-chain 

hydrocarbon substances (i.e., n-paraffins, n-alkanes) and are generally divided into three categories based on their 

carbon chain-length:

• Short-Chain Chlorinated Paraffin (SCCP): C10 to C13

• Mid-Chain Chlorinated Paraffin (MCCP): C14 to C17 

• Long-Chain Chlorinated Paraffin (LCCP): C18 to C30

For purposes of this assessment, the LCCPs are being divided into 3 subgroups to reflect differences in carbon chain 

length (those derived from the C18-C20 hydrocarbon feedstock and those from the C20-C30 hydrocarbon feedstock), and 

physical state (as a result of degree of chlorination). Both factors have an influence on use pattern, which adds to the 

usefulness of this approach. These subgroups are:

- C18-C20 LCCPs: ca. 40 – 52% Cl (liquid)

- C20-C30 LCCPs: ca. 40 – 54% Cl (liquid)

- C20-C30 LCCPs: ca. 70% Cl (solid)

LCCP purity is related to the purity of the n-paraffin feedstock. In North America and Western Europe, n-paraffin 

feedstocks contain no more than 1-2% isoparaffins and <100 ppm (<0.01%) aromatics (which are specifically removed 

from the paraffins feedstock by hydrodesulfurisation). The feedstocks may contain n-alkanes beyond the nominal or 

predominant carbon number range reported for the feedstock. The carbon number range (C18-C30) of the LCCP category 

is generally fully encompassing of the main commercial products, though some C18-20 products may contain a significant 

(10-20%) amount of C17 chlorinated alkane.

The substances in this category have a predictable range of physico-chemical properties and physical forms. As chain 

length and degree of chlorination increases, pour (melting) points and octanol-water partition coefficients increase and 

water solubilities decrease. While there are ranges to the physico-chemical properties, LCCPs all still display similar 

characteristics – very low water solubility, very low vapour pressure, and high Kow values. Environmental fate 

modelling indicates that all LCCPs are anticipated to partition almost entirely to the soil or sediment, depending on 

release patterns, indicating that fate and behaviour are likely be very similar for all LCCPs. Data from the related 

substance MCCPs, which have similar physico-chemical properties, are structurally analagous and, where known, have 

a similar toxicological profile to C18-20 LCCPs, are used to address human health hazards for C18-20 LCCPs, including 

acute toxicity, irritation, repeated dose toxicity, toxicity for reproduction (effects on fertility) and developmental 
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toxicity. Data from liquid C20-30 LCCPs is read across to solid C20-30 LCCPs for acute Daphnia magna toxicity.

Physico-chemical Properties

Measured data for commercial LCCPs usually give a range of values for single endpoints owing to the complex 

nature of the substance. Estimated values have been predicted using representative individual structures. LCCPs can 

vary from free-flowing mobile liquids, through highly viscous glassy liquids, to waxy solids and powders. Distinct 

melting points are not evident; liquid LCCPs generally exhibit pour points (approximate range -30 to 10 °C) and 

solid LCCPs softening points (103 – 115 C). Higher values correspond with a greater degree of chlorination. 

LCCPs decompose at temperatures above 210 °C before boiling occurs. Vapour pressures range from 1.4 x 10-15to 

5.3 x 10-4Pa (estimated at 25 °C) for C20-30 (ca. 70% Cl) and C18-20 (ca. 40% Cl), respectively. Estimated octanolwater partition coefficients (log Kow) range from 7.5 – 11.5 for C18-20 , from 7.6 -17.5 for liquid C20-30 and from 16.9 

– 20.1 for solid C20-30 LCCPs. The estimated water solubility ranges from 1.6  10-11– 6.6 μg/L at 20 °C for LCCPs.

Human Health

Toxicokinetics, metabolism and distribution

No information was available on the metabolism of the LCCPs.

Ninety-day studies, in which 14C radio-labelled LCCPs were administered orally to rats, showed that an average of 77% 

of the administered radio-activity was excreted in the faeces within seven days. Less than 1% was excreted in urine or 

expired air. This suggests that the compound was either poorly absorbed or that a significant quantity was excreted in 

the bile, either unchanged or as a metabolite. Up to about 4% remained in the tissues, mainly the liver. There have been 

no studies on absorption through the skin. It is known that both SCCPs and MCCPs are absorbed via this route to only a 

very small extent (~0.7 % for MCCPs). It is anticipated that based on the larger molecule size of LCCPs, they would be 

less likely than MCCPs to be absorbed through the skin. Similarly, there are no studies on the absorption of LCCPs 

through the respiratory tract, either as vapour, aerosol or dust, although it is reasonable to assume that absorption via the 

lungs is unlikely to be higher than the assumed rate of oral absorption, i.e. 50%.

Acute toxicity

There is adequate data to assess the acute toxicity of LCCPs. C20-30 LCCPs (both solid and liquid) are of very low acute 

toxicity, having oral LD50 values in excess of 5.0 g/kg bw in the rat and other species. MCCPs are also of very low acute 

toxicity, with oral LD50 >2.0 g/kg bw in the rat. As such it is likely that C18-20 liquid grade LCCPs are of very low acute 

toxicity.

There are no data on the acute toxicity of LCCPs following dermal administration. However, as it is anticipated that they 

would not be absorbed to any significant extent via this route, it is considered unnecessary to conduct such tests. 

Similarly, there are no data on the acute toxicity of LCCPs following inhalation. 

Irritation

There is adequate data to assess the irritant potential of LCCPs. In a study of liquid C20-30 LCCPs, 0.5 ml neat LCCP, 

which included several stabilisers, was applied as a single occlusive application for 24 hours to abraded and non-abraded 

skin of rabbits. Erythema and oedema was scored after 24 and 72 hours. Slight erythema was observed on both the 

abraded and non-abraded skin in two out of six rabbits at 24 hours. In another study, up to 6 applications of 0.1ml of 

either liquid or solid LCCPs, either neat or in a non-irritating vehicle, were applied to the shorn back of three female rats 

on alternate 24-hour periods. It was concluded that these test materials were non-irritant. Single exposure to MCCPs also 

caused slight irritation in standard tests, but somewhat more pronounced irritation has been reported following repeated 

exposure, presumably due to the defatting properties of MCCPs. There are no data on respiratory irritation of LCCPs, 

Overall the only concern regarding skin irritant properties of LCCPs relates to read across data from MCCPs which may 

be applicable to C18-20 LCCPs. C20-30 LCCPs do not possess irritating properties.

Sensitisation

Valid skin sensitisation studies on LCCPs in guinea pigs have shown no evidence of sensitising potential. These 

findings, together with the lack of sensitisation activity shown by SCCPs and MCCPs, support the conclusion that 

LCCPs are unlikely to have any significant potential to sensitise the skin. 

Repeat-dose toxicity

There are valid oral 90-day repeat dose toxicity studies in the rat on a C23(average), 43%Cl LCCP, a C22-26, 43 % Cl LCCP 

(both liquid grades) and a C22-28, 70% Cl LCCP (a solid grade) which have been conducted to protocols which are 

broadly consistent with modern guidelines. There are also a valid oral 90-day repeat dose toxicity study in the mouse 

and valid 2-year repeat dose studies in both the rat and the mouse on the C23(average), 43%Cl LCCP.

Studies in rats: The principal target organ in the rat for 90-day and 2-year studies was the liver, with the lymphatic 

system and kidneys in male rats and the haematological system in female rats also identified as target organs. The 
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female rat was the most sensitive sex and species. In the 90-day study of C22-28, 70% Cl solid LCCP, the NOAEL for 

both male and female rats was 900 mg/kg bw/day based on hepatotoxicity at 3750 mg/kg bw/day (LOAEL). In a 90-day 

study of C23(average), 43%Cl LCCP, no significant adverse effects were observed in the male rats (NOAEL =3750 mg/kg 

bw/day), but effects in the liver (granulomatous inflammation) were observed in all dose groups for the females 

(LOAEL of 235 mg/kg bw/day). In a 90-day study of C22-26, 43 % Cl liquid LCCP, there was evidence of liver toxicity 

in all exposed females (increased absolute liver weight, dose-dependent multifocal granulomatous hepatitis accompanied 

by an increase in the intensity of ORO staining, a slight increase in microsomal Lowry protein and a concomitant 

increase in microsomal enzyme levels). There were no effects in the livers of treated male rats, although trace/mild 

nephrosis was reported in male rats receiving 3750 mg/kg/day. The NOAEL for male rats from this study was 900 

mg/kg bw/day and the LOAEL for female rats was 100 mg/kg bw/day (no NOAEL could be established). In the 2-year 

study of rats with C23(average), 43%Cl LCCP, increased liver weights were seen in both male and female rats, the effect 

being seen after 6 months dosing in female rats and after 12 months dosing in male rats. The effects were accompanied 

by a slight elevation in several serum enzyme levels and, in females only, variations in haematological parameters. The 

primary pathological lesion reported was a diffuse lymphohistiocytic inflammation of the liver and the pancreatic and 

mesenteric lymph nodes. The LOAEL for effects in the liver was 1875 mg/kg bw/day in male rats and 100 mg/kg 

bw/day in female rats.

Studies in mice: In the mouse, oral administration of the C23 (average), 43 % Cl LCCP for either 90-days or 2-years caused 

no effects on body or organ weights, no clinical signs of toxicity and no treatment-related histopathological effects (90-

day NOAEL = 7500 mg/kg bw/day; 2-year NOAEL= 5000 mg/kg bw/day).

The LOAEL for C20-30 LCCPs in 90 day and 2 year studies in the rat was 900 mg/kg bw/day in males and 100 mg/kg 

bw/day in females, based on hepatotoxicity. The NOAEL for males in the 90 day study was 300 mg/kg bw/day, but no 

NOAEL was obtained for females.

There was no valid repeat-dose toxicity study on a C18-20 liquid grade LCCP, though available data on MCCPs, C14-17, 

was used for read across purposes. In a 90-day rat dietary study, using MCCP, decreased plasma triglycerides and 

cholesterol, and increased kidney weights were observed at 222 mg/kg bwt/day, and the NOAEL was 23 mg/kg bw/day.

This NOAEL can be read across to C18-20 LCCPs.

Mutagenicity

There is adequate data to assess the mutagenic potential of LCCPs. LCCPs, like the SCCPs and the MCCPs, do not 

induce mutations in bacteria. There is some evidence of weak clastogenic potential in vitro in mammalian cells, with

chromosomal aberrations observed in CHO cells (with metabolic activation) and also sister chromatid exchanges (at 5-

5000 μg/mL with and without activation); however, no evidence of chromosomal aberrations was seen in a wellconducted in vivo study in rat bone marrow cells, in which the rats received doses of up to 5000 mg/kg bw/day for 5 

days by gavage. There was also a negative mouse lymphoma assay conducted by the NTP on C23(average) liquid LCCP. 

Taking all of the data on LCCPs into account and considering what is known about shorter chain CPs, it is concluded 

that LCCPs, as a group, are without significant genotoxic potential.

Carcinogenicity

There are valid studies on the carcinogenic effects of a C23(average) 43%Cl LCCP in rats and mice. The only convincing 

evidence of carcinogenicity was an increased incidence of malignant lymphoma in male mice reported at the highest 

dose of 5000 mg/kg bw/day. Marginal increases in the incidence of adrenal medullary phaeochromocytomas were 

observed in female rats from 100 to 5000 mg/kg bw/day and in hepatocellular carcinomas in female mice at 5000 mg/kg

bw/day. 

These changes were only observed at exposure levels that are so high (5000 mg/kg bwt/day) that the relevance of this 

property to a human health is doubtful. 

There is no information on the carcinogenic potential of C18-20 LCCPs or C20-30 solid grade LCCPs. However, given the 

results on the studies in rats and mice on the C20-30 liquid grade LCCP and the fact that CPs, in general, are without 

significant genotoxic potential, it is considered that LCCPs present a low carcinogenic potential for humans.

Toxicity for Reproduction

Effects on Fertility: There are no fertility studies available, conducted with the LCCPs. No evidence of toxicity to the 

reproductive organs has been found in standard repeated dose studies conducted with LCCPs. In addition, no evidence 

of an adverse effect on fertility (standard reproductive/fertility parameters were unaffected) has been found in a wellconducted fertility study conducted oral gavage study of MCCPs. However, in this study, MCCPs did cause maternal 

deaths around the time of parturition, and neonatal mortalities from internal hemorrhaging as a consequence of reduced 

maternal vitamin K levels; it is possible that similar effects could be observed with LCCPs. These changes in vitamin K 

levels were only observed at doses of 74 mg/kg bw/day and above, which is significantly greater than the NOAEL of 43 

mg/kg bw/day identified for repeated dose effects established for the MCCPs. Overall, it is anticipated that the LCCPs 

are unlikely to pose a hazard to fertility.
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Developmental Toxicity: There are valid oral gavage developmental toxicity studies on both solid and liquid grade C20-30 

LCCP. There is no evidence that these grades of LCCP cause developmental effects in either rats or rabbits; NOAELs 

for developmental toxicity range from >1000 to >5000 mg/kg bw/day). There was some evidence that these grades of 

LCCP might impact on implantation and foetal survival in the rabbit in the absence of overt maternal toxicity, although 

the effect was not toxicologically significant even at 5000 mg/kg bw/day, the highest dose tested.

There was no valid developmental toxicity study on a C18-20 liquid grade LCCP. However, given the results of the studies 

on the C20-30 LCCPs and the fact that MCCPs have shown no adverse effects in prenatal developmental toxicity studies, 

it is concluded that the C18-20 liquid grade LCCPs are also likely to be devoid of developmental toxic effects. 

Overall, the LCCPs are not considered to be developmental toxicants.

LCCPs possess properties indicating a hazard for human health (repeated dose toxicity and for C18-20 LCCPs, 

potential for skin irritation). Adequate screening-level data are available to characterise the hazard to human 

health for the purposes of the OECD HPV Chemicals Programme for C20-30 LCCPs and read across data from 

MCCPs were used to characterise missing SIDS endpoints for the C18-20 LCCPs.

Environment

LCCPs have very low volatility and water solubility. LCCPs are hydrolytically stable as they contain no hydrolysable 

functional groups. Based on Mackay Level III fugacity modelling, in the environment LCCPs are expected to remain

almost entirely in the soil when released to soil and migrate to the sediment when released to water. This is also supported

by the high Kow values for LCCP, which suggest a strong affinity for soil and sediment. Estimated Koc values for LCCPs 

range between 2.93 x 106and 1 x 1010 L/kg (the upper limit of the model). Any limited amount of LCCPs in the air may 

adsorb to particulates or aerosols. Unsorbed LCCPs in air would break down via photooxidation, mediated primarily by 

hydroxyl radicals with a calculated degradation half-life range of 18 to 112 hours (based on a 12-hour day and a hydroxyl 

radical concentration of 5x105 •OH/cm3). Data indicate some potential for biodegradation with acclimated microorganisms, 

though limited biodegradation in non-acclimated organisms. The potential for biodegradation appears to increase with 

decreasing chlorine content. There is also information to suggest that biodegradation of LCCPs may occur under anaerobic 

conditions. However LCCPs are not considered to be readily biodegradable. LCCPs do not appear to be toxic to 

microorganisms in the available study data.

Studies performed mostly in excess of water solubility have shown LCCPs to bioaccumulate in fish and mussels; it is 

not possible to obtain a reliable BCF value from these data. The potential for uptake and accumulation of LCCPs by 

fish and other aquatic and terrestrial organisms appears to decrease with increasing carbon chain length and increasing 

degree of chlorination. Model estimated BCFs in fish are as follows based on representative log Kow values (EU 

Technical Guidance Document parabolic equation, applicable for substances with log Kow >6 and molecular weight < 

700 g/mol: log BCF = -0.2 x(log Kow)2+ (2.74 x log Kow – 4.72)): 

C18-20 liquid LCCP BCF = 1,096 L/kg (based on log Kow 9.7) 

C20-30 liquid LCCP BCF = 192 L/kg (based on log Kow 10.3)

C20-30 solid LCCP BCF <1 L/kg (based on log Kow 17)

Results of dietary exposure studies in fish show that uptake from food occurs in the laboratory, and that this uptake in some 

cases can be significant. The degree of uptake appears to be highest for the C18–20 LCCPs, but uptake of C20-30 LCCPs has 

also been demonstrated. The uptake of the highly chlorinated C20-30 solid LCCPs from food appears to be minimal.

There is a relatively large amount of aquatic toxicity data available for LCCPs. Aquatic toxicity testing is problematic due 

to the very low water solubility of LCCPs. In many instances, it is uncertain whether saturated test solutions contained 

undissolved test substance. It is likely that the methods used in some tests (e.g., water accommodated fraction) to 

prepare test solutions may result in the more soluble components (ie those with shorter chain lengths) present in the 

commercial LCCP being preferentially represented in the resultant solution. These, and the fact that any effects observed 

were near the limit of water solubility, complicate interpretation of test results. The substances in the category generally 

show little or no toxicity at concentrations well in excess of their water solubility in acute tests. Available acute test results 

are as follows.

C18-20 LCCPs

Fish (96h): no effects at limit of solubility.

Daphnia magna (48-h): no effects at solubility limit in one of two studies; 15% immobilisation in another study in a 

saturated solution (400 – 500 ug/l, measured). 

C20-30 liquid LCCPs 

Fish (96-h): no effects at limit of solubility.
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Daphnia magna (48h): no effects at limit of solubility.

C20-30 solid LCCPs

Fish (96-h): no effects at limit of solubility

No study is available for C20-30 solid LCCPs, but no effects are expected given no effects were seen with C20-30 liquid 

LCCPs. No valid algal study exists for any of the LCCPs, but data from related chlorinated paraffins (SCCPs and MCCPS) 

suggest that LCCPs would show no effects on algae. The overall toxicity profile of these substances (SCCP, MCCP, 

LCCPs) suggest that filling this data gap is not critical for the environmental assessment. 

Chronic studies in fish are available for C20-30 liquid and solid LCCPs. No effects were seen in the tests (NOECs equating to 

the highest concentrations tested were reported: 4 mg/l nominal and 3.8 mg/l nominal). The results may be read across to 

C18-20 LCCPs. 

Daphnia magna has been identified as the most sensitive species for chlorinated paraffins as a substance class. Two studies 

are available which investigated chronic toxicity to Daphnia magna from C18-20 LCCPs. One showed no effects at a 

saturation limit of 2 ug/L (measured) and the other, which followed a water-accommodated fraction technique, showed 

effects at 58-65 μg/L and no effects at 29 – 32 ug/L (measured). Based on these data, the worst case assumption is that the 

NOEC for C18-20 LCCPs for Daphnia magna is 29 μg/L (which is above many estimates of water solubility for LCCPs).

Available chronic studies with C20-30 liquid LCCPs in Daphnia magna indicate no effects are observed below the limit of 

water solubility; the same conclusion can be read across to C20-30 solid LCCPs.

Upon release into the environment, the substances are likely to partition to sediment in the aquatic compartment and 

bind to soil in the terrestrial environment; no data for sediment- or soil-dwelling organisms were available.

LCCPs generally show little acute aquatic toxicity at concentrations at or above water solubility. Given the 

complexity of the substances and their very low solubility interpretation of test results is not straight forward. C18-20

liquid LCCPs possess properties indicating a hazard for the environment (chronic toxicity to invertebrates). Based 

on the available data C20-30 liquid and solid LCCPs appear to present a low hazard for the environment. LCCPs are 

not readily biodegradable, and may have a potential for bioaccumulation. 

Use/Exposure

The total EU usage of LCCPs was in the range of 5,000-10,000 tonnes/year from 1998-2004. The main areas of use for 

LCCPs are as a flame retardant in rubber and textiles, and as a plasticiser/flame retardant in sealants/adhesives and 

paints. LCCPs may also be used to a lesser extent as a secondary plasticiser in PVC, as an extreme pressure additive in 

metal cutting/working fluids (oil- and/or water-based) and as a component of leather fat liquoring treatments (leather is 

treated with a fat liquor as the last step in its preparation; the fat liquor improves the feel and suppleness of the leather). 

Occupational exposure to LCCPs may occur during their manufacture, their incorporation into downstream products 

(PVC, metal working fluids, sealants, rubber, leather fat liquors, paints, textiles) and their processing, especially at high 

temperatures and during the use of these products. Occupational exposure may occur via dermal contact, though 

workers are generally advised to wear protective clothing and avoid skin contact. Exposure by inhalation is not 

expected to be a likely source of exposure due to the very low volatility of LCCPs, though there is the potential for 

aerosols to form during the use of liquid products such as metal-working fluids or by inhalation of dusts from 

applications using the solid grades. Consumer exposure may occur through use of the substance as a plasticiser or flame 

retardant in consumer goods. Exposure would primarily be via the dermal route given the substance's physico-chemical 

properties. No information on migration of the substance from articles containing it is available. The concentrations of 

the substance used in articles are typically <1 -6% in PVC, and most rubber and paints. In exceptional cases, up to 15% 

is used in cabling materials and in some rubbers. Coatings that contain LCCPs are typically only used in occupational 

settings (e.g., roadway paint). Releases to the environment could occur during production, the processing steps for the 

identified uses of the substance, use of articles containing the substance, and at end of life disposal. However, exposure 

is expected to be low from the majority of these releases. Depending on the waste disposal practices followed for waterbased emulsions for metal working fluids that may contain the substance, release of the substance to the environment 

may occur. However, the use of LCCPs in metal working fluids is expected to be minor compared to other applications.