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HIGH PRODUCTION VOLUME -2 kH 8: CHEMICAL CHALLENGE PROG 

REVISED TEST PLAN 

For 

CASHEW NUT SHELL LIQUID 

CAS NO. 8007-24-7 

Submitted to the US EPA 

Cardolite Corporation, Inc. 

www.cardolite.com 

Tabte of Contents 
Test Plan for Cashew Nut Shell Liquid 

1. Introduction 

1.1 Composition 

1.2 Commercial applications 

1.3 Worker/consumer exposure 

2. Rationale for Selection of Compound for testing 

3. Review of Existing Data and Development of Test Plan 

A. Evaluation of Existing Physicochemical Data and Proposed Testing 

B. Evaluation of Existing Environmental Fate Data and Proposed Testing 

C. Evaluation of Existing Ecotoxicity Data and Proposed Testing 

D. Evaluation of Existing Human Health Effects Data and Proposed Testing 

4. Evaluation of Data for Quality and Acceptability 

5. References 

6. Robust Summaries 
1. Introduction 

Cashew nut shell liquid (CNSL) is one of the sources of naturally occurring phenols. It is 

obtained from the shell of a cashew nut. About 30-35% CNSL is present in the shell, 

which amounts to approximately 67% of the nut. 

CNSL is traditionally obtained as a by-product during the process of removing the cashew 

kernel from the nut. The processes used are mainly hot-oil and roasting in which the 

CNSL oozes out from the shell. 

The cashew tree is cultivated globally in tropical areas such as East Africa, South and 

Central America and the Far East. The world availability of CNSL is in the region of 

50,000 tons/year. 

1.1 Composition 

Natural (i.e. cold, solvent extracted) CNSL contains approximately 70% anacardic acid 

(Fig 1), 18% cardol, and 5% cardanol, with the remainder being made up of other phenols 

and less polar substances. As can be seen in Figure 1, anacardic acid, cardanol and 

cardol consist of mixtures of components having various degrees of unsaturation in the 

alkyl side-chain. 

Figure 1: Structures of Anacardic acid, Cardanol and Cardol 
In technical (i.e. heat extracted) CNSL, the heating process leads to decarboxylation of the 

anacardic acid to form cardanol. Typically, the composition of technical CNSL is 

approximately 52% cardanol, 10% cardol, 30% polymeric material, with the remainder 

being made up of other substances. 

The technical CNSL is often further processed by distillation at reduced pressure to 

remove the polymeric material. The composition of distilled technical CNSL is 

approximately 78% cardanol, 8% cardol, 2% polymeric material, < 1% 2-methyl cardanol, 

2.3% heptadecyl homologue triene, 3.8% heptadecyl homologue diene and the remainder 

other homologous phenols. 

Table 1 summarises the composition of typical batches of technical and distilled technical 

grades of CNSL. 

Table 1: Composition of typical batches of Technical and Distilled CNSL 

Cardanol Cardanol 

monoene 

Cardanol 

diene 

Cardanol 

triene 

Cardol 

diene 

Cardol 

triene 

Polymer 2-methyl 

cardanol

C17 

triene

C17 

diene 

Unidentified 

phenols 

T-CNSL 0.06 17.10 10.78 24.42 2.36 7.50 30.6 5.83 

D-CNSL - 25.9 16.2 35.8 2.04 5.90 2.5 0.60 2.27 3.75 5.04 

AT-CNSL 0.09 24.7 15.6 35.3 3.41 10.8 - 8.42 

T-CNSL = Technical grade, D-CNSL = Distilled grade, AT-CNSL = Technical grade component percentages adjusted for 

removal of polymer. 

1.2 Commercial Applications 

CNSL resins have been used extensively in the manufacture of friction-resistant 

components in applications such as brake and clutch linings. These resins are used as 

binders for friction ingredients and also as friction ingredients themselves in the form of 

fine dusts obtained from the completely cured resins. 

CNSL-aldehyde condensation products and CNSL-based phenolic resins are used in 

applications such as surface coatings, adhesives, varnishes and paints. Various 

polyamines synthesised from CNSL or cardanol are used as curing agents for epoxy 

resins. 

CNSL and its derivatives have been used as antioxidants, plasticisers and processing aids 

for rubber compounds and modifiers for plastic materials. Resins based on the reaction 

products of cardanol phenol and formaldehyde are used to improve the resistance of 

rubber articles to cracking and ozone. CNSL, cardanol and cardol are all used to provide 

oxidative resistance to sulfur-cured natural rubber products. Cardanol, CNSL or sulfurated 

CNSL is added to rubber gum stock or nitrile rubber to improve the processability, 

mechanical properties and resistance to crack and cut properties of the vulcanisates. 

A number of products based on CNSL are used as antioxidants, stabilisers and 

demulsifiers for petroleum products. Metal xanthates of partially hydrogenated, sulfurised 

cardanol is used to lower the pour point of lubricating oils as well as acting as antioxidant 

and anticorrosive properties. Soluble metal derivatives of CNSL are used to improve the 

resistance to oxidation and sludge formation of lubricating oils. Oxidised CNSL and its 

derivatives are used as demulsifying agents for water in oil type petroleum emulsions. 

1.3 Worker/consumer exposure 
Only large industrial manufacturers use CNSL. There are no direct consumer applications 

and therefore no direct sales to the general public. The most likely source of consumer 

exposure to CNSL is through contact with contaminated nuts, although reports of adverse 

effects arising from such contact appear to be rare. 

Exposure of workers to CNSL during production is most likely to occur during removal of 

the kernels from the nuts, after processing to remove the CNSL, especially in countries 

where the shelling has not been mechanised. Exposure to CNSL can lead to sensitisation 

and dermatitis. Workers in these countries are given some protection to exposure through 

the use of barrier creams. 

Workers involved in the further processing the CNSL to manufacture commercial products 

are likely to have minimal exposure to the CNSL as it is expected that good industrial 

hygiene practices will be followed and personal protective equipment worn to minimise 

exposure. 

2. Rationale for Selection of Compounds for testing 

Distilled Technical CNSL has been selected as the most suitable substance for testing to 

fulfil the requirements of the HPV Challenge Program. This is because it is possible to 

obtain distilled CNSL to a more consistent specification than the Technical CNSL and the 

distilled grades are becoming more important industrially than the crude technical grade 

material. It is also believed that since all of the substances in CNSL are based on phenols 

having various degrees of unsaturation in the side chain, they meet the EPA’s criterion of 

using the ‘family approach’, thus the toxicological properties of the Distilled CNSL will be 

representative of the properties of the Technical CNSL. 

3. Review of Existing Data and Development of Test Plan 

Cardolite Corporation has undertaken a comprehensive evaluation of all relevant data on 

the SIDS endpoints of concern for Cashew Nut Shell Liquid. 

The availability of the data on the specific SIDS endpoints is summarized in Table 2. 

Table 2 also shows data gaps that will be filled by additional testing. 

Table 2: Available Adequate Data and Proposed Testing on Cashew Nut Shell Liquid* 

CAS No. 8007-24-7 

Information 

Available? 

GLP 

OECD 

Study? 

Other 

Study? 

Estimation 

Method? 

Acceptable? 

SIDS 

Testing 

re

quired? 

Y/N Y/N Y/N Y/N Y/N Y/N Y/N 

Physicochemical 

Vapour Pressure Y Y Y - N Y N 

Partition Coefficient (Kow) Y Y Y - N Y N 

Water solubility Y Y Y - N Y N 

Environmental Fate & Pathway 

Photodegradation Y N N - Y Y N 

Transport and distribution Y N N - Y Y N 

Biodegradation Y Y Y - - Y N 

Ecotoxicology 

Acute Fish Y - - - Y Y N 
Acute Daphnia Y - - - Y Y N 

Acute Algae Y - - - Y Y N 

Toxicology 

Acute Oral Y Y - - - Y- N** 

Repeat Dose toxicity Y Y Y - - Y N 

Genetic toxicity – Gene mutation Y Y Y - - Y N 

Genetic toxicity – Chromosome aberration Y Y Y - - Y N 

Reproductive toxicity Y Y Y - - Y N 

Developmental toxicity/teratogenicity Y Y Y - - Y N 

* No testing has been conducted for melting point, boiling point or hydrolysis. 

** This endpoint has been filled using information from the OECD 422 range-finding study 

A. Evaluation of Existing Physicochemical Data 

1. Melting Point 

Melting point will not be determined, as the substance is a liquid under ambient conditions. 

2. Boiling Point 

A boiling point at ambient pressure has no significance, as the substance will be subject to 

thermal polymerization and decomposition before boiling. Accordingly, measurement of 

this property is inappropriate for this substance. 

3. Vapor Pressure 

The vapour pressure of cashew nutshell liquid, determined in a GLP study using a vapour 

pressure balance method (OECD TG104, OPPTS 830.7950), is 5.0x10-5 Pa at 25°C. 

4. Water solubility 

The water solubility of cashew nutshell liquid, determined in a GLP study using the shake 

flask method (OECD TG 105, OPPTS 830.7840), is 3.04x10-4 g/L of solution at 20°C. 

5. Partition Coefficient 

The partition coefficient of cashew nutshell liquid, determined in a GLP study using the 

HPLC method (OECD TG117, OPPTS 830.7570), is log Pow > 6.20. 

Summary of Physicochemical Properties Testing: 

The water solubility was determined to be 3.04x10-4 g/L of solution at 20°C in a guideline 

study (OECD TG 105, OPPTS 830.7840) performed to GLP. The vapour pressure was 

determined to be 5.0x10-5 Pa at 25°C in a guideline study (OECD TG104, OPPTS 

830.7950) performed to GLP. The partition coefficient of all components of cashew 

nutshell liquid was determined to be log Pow > 6.20 in a guideline study (OECD TG 117, 

OPPTS 830.7570) performed to GLP. Tests for melting point and boiling point are not 

applicable to these substances.

B. Evaluation of Existing Environmental Fate Data 

1. Biodegradation 
Distilled CNSL has been shown to be biodegradable when tested using OECD Method 

301D (96% degradation after 28 days) in a GLP study. 

2. Hydrolysis 

Hydrolysis as a function of pH is used to assess the stability of a substance in water. 

Hydrolysis is a reaction in which a water molecule (or hydroxide ion) substitutes for 

another atom or group of atoms present in an organic molecule. None of the major 

components of CNSL contain a functional group that would be susceptible to hydrolysis. 

Therefore, hydrolysis need not be measured. 

In addition, low water solubility often limits the ability to determine hydrolysis as a function 

of pH. The water solubility of cashew nutshell liquid was determined to be 3.04x10-4 g/L. 

Therefore, these materials are expected to be stable in water and it would be unnecessary 

to attempt to measure the products of hydrolysis. 

3. Photodegradation 

Indirect photo-oxidation by hydroxy radicals (1500000 molecule/cm3) is predicted to occur 

with a half-life estimated at 0.351-1.254 hrs (calculated using AOPWIN v1.91 at 25 °C, rate 

constant, 102.3748 – 365.8109 E-12 cm3/molecule/sec, 12-hour day). 

4. Transport and Distribution between Environmental Compartments 

Based on Epiwin V3.12 Level III Fugacity Model estimations, the major components of 

cashew nutshell liquid will distribute mainly to soil (37.3 - 77.7%) if released to the air 

compartment, almost exclusively to sediment (94.8 – 97.3%) if released to water, 

exclusively to soil if released to soil and mainly to sediment (66.9 – 69.9%) if released 

simultaneously to all air, soil and water compartments. 

Summary of Environmental Fate Testing: 

Distilled CNSL has been shown to be biodegradable when tested using OECD Method 

302D (96% degradation after 28 days) in a GLP study. None of the major components of 

CNSL contain a functional group that would be susceptible to hydrolysis. Indirect photooxidation by hydroxy radicals (1500000 molecule/cm3) is predicted to occur with a half-life 

estimated at 0.351-1.254 hrs (calculated using AOPWIN v1.91 at 25 °C, rate constant, 

102.3748 – 365.8109 E-12 cm3/molecule/sec, 12-hour day). Based on Epiwin V3.12 

Level III Fugacity Model estimations, the major components of cashew nutshell liquid will 

distribute mainly to soil (37.3 - 77.7%) if released to the air compartment, almost 

exclusively to sediment (94.8 – 97.3%) if released to water, exclusively to soil if released to 

soil and mainly to sediment (66.9 – 69.9%) if released simultaneously to all air, soil and 

water compartments. 

C. Evaluation of Existing Ecotoxicity Data 

The basic ecotoxicity data that are part of the HPV program include acute toxicity to fish, 

daphnia and algae. Predicted values for the 2 main chemical components, and their 
analogs, of CNSL have been obtained using ECOSAR v 0.99e (1). These values predict 

that CNSL will be toxic in the aquatic environment, therefore it is unnecessary to generate 

experimental data. This is further supported by the low solubility of CNSL, which is 

3.04x10-4 g/L of solution at 20°C, making analytical monitoring of the tests very difficult and 

making the tests themselves unlikely to determine any more useful or accurate estimates 

of toxicity than the estimations. 

Summary of Ecotoxicity Testing: 

The 2 main components of CNSL, and their analogs, are predicted to be acutely toxic to 

fish (LC50 (96h) < 11x10-3 mg/l), daphnia (LC50 (48h) < 66x10-3 mg/l) and algae (EC50 (96h) 

< 1x10-3 mg/l). 

D. Evaluation of Existing Human Health Effects Data and Proposed Testing 

1. Acute Oral Toxicity 

In a 14-day range-finding study, performed as part of the combined repeat dose 

reproduction/developmental toxicity screening test (OECD TG 422) no mortality or clinical 

signs of toxicity were observed at the maximum dose of 1000 mg/kg bw/day. It is 

concluded that the LD50 for acute oral toxicity is likely to be greater than 1000 mg/kg bw. 

2. Repeat Dose Toxicity 

In a combined repeat dose reproduction/developmental toxicity screening study (OECD 

422, GLP), male and female rats were dosed by gavage daily with CNSL in arachis oil at 

0, 15, 150 or 1000 mg/kg bw/day for up to 49 days. There were no treatment-related 

deaths during the study. A slightly reduced bodyweight gain was observed for 1000 

mg/kg/day males during the first two weeks of the study. Reduced bodyweight gain was 

also observed for 1000 mg/kg/day females during the later stages of the gestation period. 

No adverse effect on dietary intake or food efficiency was detected. No intergroup 

differences in water consumption were detected. Increased salivation was detected prior to 

dosing and up to five hours after dosing for animals of either sex treated with 1000 

mg/kg/day from Day 9 onwards. An isolated incident of increased salivation was detected 

up to one hour after dosing for one male treated with 150 mg/kg/day on Day 8 only. One 

female treated with 150 mg/kg/day developed hunched posture, pilo-erection, tiptoe gait, 

red/brown staining around the mouth, laboured respiration and pallor of the extremities on 

Day 5 and was subsequently terminated due to the severity of these observations. On Day 

39 of the study (gestation Day 21), one female treated with 1000 mg/kg/day showed 

staining around the vagina, hunched posture, tiptoe gait, pilo-erection, pallor of the 

extremities and red/brown staining around the snout. This animal had given birth to a total 

of sixteen pups, twelve of which were found dead. This animal, together with the live pups 

were subsequently terminated on humane grounds. No such observations were observed 

for animals of either sex treated with 15 mg/kg/day. Increased salivation was detected for 

individual animals of either sex treated with 1000 mg/kg/day during the Week 3 and Week 

4 assessments. This observation was also observed for two 1000 mg/kg/day males during 

the post-mating assessments and for one 1000 mg/kg/day female during the Day 4 post 

partum assessments. No such effects were detected for animals of either sex treated with 

150 or 15 mg/kg/day. All remaining inter and intra group differences in urination, 

defecation and transfer arousal scores were considered to be a result of normal variation 

for rats of the strain and age used and were of no toxicological importance. There were no 

treatment-related changes in the functional performance parameters measured or in 
sensory reactivity. Elevated platelet counts were observed for males treated with 1000 

mg/kg/day during the pre-mating and pre-termination investigations. Elevated 

haemoglobin, erythrocyte and haematocrit counts were also evident for 1000 mg/kg/day 

males during the pre-mating and pre-termination investigations. Males treated with 1000 

mg/kg/day also displayed elevated mean cell volume (MCV) and a reduction in mean cell 

haemoglobin concentration (MCHC) during the pre-mating and pre-termination 

investigations. An increase in MCV was also seen for 1000 mg/kg/day females during premating and terminal assessments. Although the aetiology of these changes is unclear, the 

level of significance achieved for haematocrit and MCHC cannot be disregarded. No 

treatment-related effects were detected for animals of either sex treated with 150 or 

15 mg/kg/day. Elevated aspartate aminotransferase, alanine aminotransferase, alkaline 

phosphatase and inorganic phosphorus were detected for animals of either sex with 1000 

mg/kg/day during blood chemical investigations. A reduction in cholesterol and elevated 

bilirubin levels were also detected, with effects more prominent in the males, which also 

showed a slight increase in plasma urea, reduction in glucose levels and elevated 

albumin/globulin ratios during the pre-termination investigations. No such observations 

were detected for animals of either sex treated with 150 or 15 mg/kg/day. No treatmentrelated microscopic abnormalities were detected at terminal kill. Females treated with 

1000 mg/kg/day showed a statistically significant increase in relative liver weight. Absolute 

liver weight was also elevated, but statistical significance was not achieved. An increase 

in absolute and relative adrenal weight was also observed for females. No such 

observations were detected for 1000 mg/kg/day males or for animals of either sex treated 

with 150 or 15 mg/kg/day. The following treatment related changes were found: Lungs - 

Groups of alveolar macrophages were seen with a higher incidence for females treated 

with 1000 mg//kg/day only; Mesenteric lymph nodes - A higher incidence of sinus 

histiocytosis and/or foamy histiocytes, was observed in relation to treatment for animals 

treated with 1000 mg/kg/day but not at any other dose level; Stomach - Hyperkeratosis, 

frequently associated with acanthosis, was seen in the forestomach of animals of either 

sex treated with 1000 mg/kg/day. Focal ulceration of the forestomach epithelium was also 

seen for one high dose female. Treatment-related changes did not extend to the remaining 

treatment groups; Duodenum - Mucosal hypertrophy was seen in three males treated with 

1000 mg/kg/day. A low incidence of mucosal hypertrophy was observed in all groups of 

females. The ‘No Observed Effect Level’ (NOEL) for systemic toxicity was therefore 

considered to be 150 mg/kg/day.

3. Genotoxicity 

Distilled CNSL has been tested for potential genotoxicity in the Ames Salmonella assay 

(strains TA1535, TA1537, TA1538, TA98 and TA100), an in vitro chromosome aberration 

test in human lymphocytes, and an in vitro HGPRT forward mutation assay using a 

Chinese Hamster Ovary cell line. None of these test systems showed any indication of 

genotoxicity. All three studies were conducted under GLP. 

4. Reproductive and Developmental Toxicity 

In a combined repeat dose reproduction/developmental toxicity screening study (OECD 

422, GLP), male and female rats were dosed by gavage daily with CNSL in arachis oil at 

0, 15, 150 or 1000 mg/kg bw/day from 14 days prior to mating up to Day 4 post partum. 

Parental effects are described in the repeat dose toxicity section. There were no 

treatment-related intergroup differences in litter sizes. The intergroup variability in live litter 

size at birth and through early lactation was not reflected in any difference in percentile pre 

and post implantation loss and there was no significant increase in post partum 
invariability. There was no treatment-related difference in live birth index or viability index 

after 4 days and no toxicologically significant clinical findings were observed in offspring. 

No treatment-related macroscopic abnormalities were detected at terminal kill. No 

treatment-related effects were detected in postnatal growth. A statistically significant 

reduction in litter weight gain was detected in offspring of females treated with 1000 

mg/kg/day in comparison to controls; however this was most probably a consequence of 

smaller litter numbers in the high dose and in the absence of intergroup differences in 

mean pup weight was not considered a reproductive effect of treatment. The NOEL for 

reproductive and developmental toxicity was considered to be 1000 mg/kg/day. 

5. Skin Sensitisation 

This non-SIDS endpoint has been evaluated using distilled CNSL in a Guinea pig 

maximisation test (OECD 406). The test substance produced a 70% (14/20) sensitisation 

rate and was classified as a strong sensitiser. 

6. Oestrogenic Activity 

This non-SIDS endpoint has been evaluated using two grades of distilled CNSL in a 

recombinant yeast screen assay. The two distillates showed no oestrogenic activity under 

the conditions of the test. 

Summary of Human Health Effects Testing: 

Results from a 14-day repeat dose range-finding study indicate that the LD50 for acute 

oral toxicity is likely to be greater than 1000 mg/kg bw. In a combined repeat dose with 

reproduction/developmental toxicity study (OECD 422, GLP), the oral administration of 

CNSL to rats by gavage at the maximum dose level of 1000 mg/kg/day resulted in 

treatment-related systemic changes in the lungs, mesenteric lymph node, stomach, and 

duodenum. The ‘No Observed Effect Level’ (NOEL) for systemic toxicity was therefore 

considered to be 150 mg/kg/day. No effect of treatment was detected on reproduction or 

offspring development, therefore the NOEL for reproductive and developmental toxicity 

was considered to be 1000 mg/kg/day. Distilled CNSL has been tested and found 

negative in three in vitro genotoxicity assays therefore no additional testing for this 

endpoint will be undertaken. Distilled CNSL has been shown to be a strong skin sensitiser 

in guinea pigs and to have no oestrogenic activity when tested in a recombinant yeast 

screen assay. 

4. Evaluation of Data for Quality and Acceptability

The collected data were reviewed for quality and acceptability following the general US 

EPA guidance (3) and the systematic approach described by Klimisch et al (4). These 

methods include consideration of the reliability, relevance and adequacy of the data in 

evaluating their usefulness for hazard assessment purposes. This scoring system was 

only applied to ecotoxicology and human health endpoint studies per EPA 

recommendation (5). The codification described by Klimisch specifies four categories of 

reliability for describing data adequacy. These are: 

(1) Reliable without restriction: Includes studies or data complying with Good 

Laboratory Practice (GLP) procedures, or with valid and/or internationally accepted 

testing guidelines, or in which the test parameters are documented and comparable 

to these guidelines. 
(2) Reliable with Restrictions: Includes studies or data in which test parameters are 

documented but vary slightly from testing guidelines. 

(3) Not Reliable: Includes studies or data in which there are interferences, or that use 

non-relevant organisms or exposure routes, or which were carried out using 

unacceptable methods, or where documentation is insufficient. 

(4) Not Assignable: Includes studies or data in which insufficient detail is reported to 

assign a rating, e.g. listed in abstracts or secondary literature. 

7. References 

1. ECOSAR v0.99e. EPIWIN modelling program. Meylan, W. & Howard, P. (1999), 

Syracuse Research Corporation, Environmental Science Center, 6225 Running 

Ridge Road, North Syracuse, NY 13212-2510 

2. USEPA (1998). Guidance for Meeting the SIDS Requirements (The SIDS Guide). 

Guidance for the HPV Challenge Program. Dated 11/2/98. 

3. Klimisch, H.-J., et al (1997). A Systematic Approach for Evaluating the Quality of 

Experimental Toxicological and Ecotoxicological Data. Regul. Toxicol. Pharmacol. 

25:1-5 

4. USEPA (1999). Determining the Adequacy of Existing Data. Guidance for the HPV 

Challenge Program. Draft dated 2/10/99.