Naphthalene

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

25 mg/m³

Most sensitive endpoint:

repeated dose toxicity

DNEL related information

DNEL derivation method:

other: National OEL (EU and USA) of generally 50 mg/m3 based on human experience (in accordance with ECHA REACH Guidance R8).

Overall assessment factor (AF):

2

Modified dose descriptor starting point:

other: not applicable

Explanation for the modification of the dose descriptor starting point:

not applicable

AF for dose response relationship:

1

Justification:

not applicable

AF for differences in duration of exposure:

1

Justification:

8 h shift used as basis

AF for interspecies differences (allometric scaling):

1

Justification:

not applicable

AF for other interspecies differences:

1

Justification:

not applicable

AF for intraspecies differences:

1

Justification:

not applicable

AF for the quality of the whole database:

1

Justification:

human experiences: exposed workers

AF for remaining uncertainties:

2

Justification:

No empirical reason to withdraw the currently accepted national OEL of 50 mg/m3. Hence, AF of 2 considered sufficient to compensate for apparent uncertainties.

Acute/short term exposure

Hazard assessment conclusion:

low hazard (no threshold derived)

Most sensitive endpoint:

acute toxicity

Route of original study:

By inhalation

DNEL related information

DNEL derivation method:

other: not derived

Modified dose descriptor starting point:

other: not applicable

Explanation for the modification of the dose descriptor starting point:

not applicable

Local effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

25 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: National OEL (EU and USA) of generally 50 mg/m3 based on human experience (in accordance with ECHA REACH Guidance R8).

AF for dose response relationship:

1

Justification:

not applicable

AF for differences in duration of exposure:

1

Justification:

not applicable

AF for interspecies differences (allometric scaling):

1

Justification:

not applicable

AF for other interspecies differences:

1

Justification:

not applicable

AF for intraspecies differences:

1

Justification:

covered by factor 2 for residual uncertainties

AF for the quality of the whole database:

1

Justification:

covered by factor 2 for residual uncertainties

AF for remaining uncertainties:

2

Justification:

No empirical reason to withdraw the currently accepted national OEL of 50 mg/m3. Hence, AF of 2 considered sufficient to compensate for apparent uncertainties.

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: not derived

Workers - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

3.57 mg/kg bw/day

Most sensitive endpoint:

repeated dose toxicity

DNEL related information

DNEL derivation method:

ECHA REACH Guidance

Explanation for the modification of the dose descriptor starting point:

The starting point is the long-term DNEL(inhal., systemic) of 25 mg/m3, because this approach results in a DNEL(dermal) lower than derived from animal test.

Justification:

not applicable

AF for differences in duration of exposure:

1

Justification:

inhalation as well as dermal exposure relate to the workers´shift of 8 h.

Justification:

not applicable

Justification:

not applicable

AF for intraspecies differences:

1

Justification:

included in DNEL(inhal.)

Justification:

not applicable: included in DNEL(inhal.)

Justification:

not applicable: included in DNEL(inhal.)

Acute/short term exposure

Hazard assessment conclusion:

low hazard (no threshold derived)

Most sensitive endpoint:

acute toxicity

Route of original study:

Dermal

DNEL related information

DNEL derivation method:

other: not derived

Modified dose descriptor starting point:

other: not applicable

Local effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

sensitisation (skin)

DNEL related information

Dose descriptor:

other: not applicable

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

skin irritation/corrosion

DNEL related information

Dose descriptor starting point:

other: not applicable

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

no hazard identified

Additional information - workers

NOTE: Naphtthalene has to be classified as Carc. Cat, 2. This does not require to derive a DMEL. Moreover, it has become more and more evident that the relevance in humans of findings in rodents as to its carcinogenic potential is poor. This also justifies to use a DNEL that is based on endpoints with human relevance for risk characterisation.

The potential hazardous effects of naphthalene on human health may concern:

 

·        haemolytic anaemia following single and repeated exposure;

·        nasal lesions following repeated inhalation exposure; and

·        carcinogenicity of the nasal epithelium. 

 

1.       DNEL Acute systemic dermal

There is a reasonable animal toxicity database available for naphthalene. In relation to acute toxicity, naphthalene is of low single dose toxicity in rats, but there appear to be some species differences in that the mouse shows a greater sensitivity to the acutely lethal effects of naphthalene than the rat, presumably reflecting differences in metabolism. It is apparent that the main experimental species (rats, mice and rabbits) do not provide a suitable model for naphthalene-induced haemolytic anaemia, a principal toxicological effect of naphthalene in humans. Given that neither species shows haemolytic anaemia at the doses administered, the information from acute toxicity studies is not considered to be relevant to humans. Therefore, the only option is to use information from the available human case reports for assessing the risks of haemolytic anaemia. In humans, the occurrence of haemolytic anaemia has been reported following dermal exposure to naphthalene from clothing. In some cases (particularly neonates) the naphthalene-induced haemolytic anaemia proved fatal, although it is not possible to determine the doses involved from the reports available. Overall, due to a lack of quantitative information on the exposures producing haemolytic anaemia in humans, the nature of the dose-response relationship cannot be identified. Whilst it is clear that humans are susceptible to haemolytic anaemia following exposure to naphthalene via the dermal route there is insufficient information available for an adequate risk characterisation and to develop an acute systemic dermal DNEL. Nevertheless, the DNEL for systemic effects caused by long-term dermal exposure is considered to be suitable for systemic effects after acute dermal exposure.

 

2.       DNEL Acute systemic inhalation

There is a reasonable animal toxicity database available for naphthalene. In relation to acute toxicity, naphthalene is of low single dose toxicity in rats, but there appears to be some species differences in that the mouse shows a greater sensitivity to the acutely lethal effects of naphthalene than the rat, presumably reflecting differences in metabolism. It is apparent that the main experimental species (rats, mice and rabbits) do not provide a suitable model for naphthalene-induced haemolytic anaemia, a principal toxicological effect of naphthalene in humans. Given that neither species shows haemolytic anaemia at the doses administered the information from acute toxicity studies is not considered to be relevant to humans. Therefore, the only option is to use information from the available human case reports for assessing the risks of haemolytic anaemia. In humans, the occurrence of haemolytic anaemia has been reported following inhalation exposure to naphthalene. In some cases (particularly neonates) the naphthalene-induced haemolytic anaemia proved fatal, although it is not possible to determine the doses involved from the reports available. Overall, due to a lack of quantitative information on the exposures producing haemolytic anaemia in humans, the nature of the dose-response relationship cannot be identified. Whilst it is clear that humans are susceptible to haemolytic anaemia following exposure to naphthalene via the inhalation route there is insufficient information available for an adequate risk characterisation andto develop an acute systemic inhalation DNEL. Nevertheless, the DNEL for systemic effects caused by long-term inhalation is considered to be suitable for systemic effects after acute inhalation.

 

DNEL Acute local dermal

There is no information available to draw conclusions regarding the irritant properties of naphthalene in humans. Data from animal studies indicate that naphthalene is only a slight skin and eye irritant insufficient to warrant classification. There is no information available on skin sensitisation in humans or respiratory sensitisation in humans or animals. In animal skin sensitisation studies, negative results were obtained in both a maximisation and a Buehler study. Naphthalene is not classified as hazardous with respect to acute local dermal effects.A survey conducted among 12 European abrasive producers in 2010 has shown that in the last 15 years (in some cases up to 40 years) of naphthalene use in the abrasives industry at least 200 workers have been regularly exposed to naphthalene vapours and dust. Companies confirmed by statements of their company doctors that skin irritation or corrosion have never been observed although there are active systems in place to pick up health complaints and adverse reaction reports. Furthermore no other observations have been made concerning any kind of occupational health effects following exposure to naphthalene dust or vapour.The use of naphthalene for many years in occupational and consumer settings (e.g. mothballs) and the absence of reports on skin irritations suggest that dermal irritation and sensitisation are not of concern for human health. Thus, in accordance with Annex I of Regulation (EC) No 1907/2006 a DNEL has not been calculated.

 

3.       DNEL Acute local inhalation

There is no information available on respiratory irritation or sensitisation in humans. A single four-hour exposure of 77.7 ppm of naphthalene produced slight clinical signs of ocular and respiratory irritation in rats. The 77.7 ppm concentration was the highest naphthalene vapour concentration obtainable under the conditions of the study. There were no clinical signs observed following the exposure or during the 14-day post-exposure period. Naphthalene is not classified as hazardous with respect to acute local effectsA survey conducted among 12 European abrasive producers in 2010 has shown that in the last 15 years (in some cases up to 40 years) of naphthalene use in the abrasives industry at least 200 workers have been regularly exposed to naphthalene vapours and dust. Companies confirmed by statements of their company doctors that skin irritation or corrosion have never been observed although there are active systems in place to pick up health complaints and adverse reaction reports. Furthermore no other observations have been made concerning any kind of occupational health effects following exposure to naphthalene dust or vapour. The use of naphthalene for many years in occupational and consumer settings (e.g. mothballs) and the absence of reports on respiratory irritation after acute exposure to naphthalene suggest respiratory irritation or sensitisation are not of concern for human health. In accordance with Annex I of Regulation (EC) No 1907/2006 a DNEL has not been calculated.

 

4.       DNEL Long-term systemic dermal

 

Step 1 – Select dose descriptor

The key dose descriptor for deriving a DNEL for systemic effects of long-term dermal exposure is a NOAEL for systemic toxicity of 1,000 mg/kg/day (the highest dose tested) which was identified in a 90-day dermal route rat study.

 

Step 2 – Determine mode of action

It is assumed that potential systemic effects in the rat are a consequence of naphthalene metabolites, for which an identifiable threshold of effect exists.

 

Step 3 – Modify dose descriptor

The DNEL is being derived for the dermal route. The dose descriptor has been obtained from a dermal study. Toxicokinetics data indicate that naphthalene is readily absorbed by all routes. It is appropriate to assume 100% bioavailability via skin and hence there is no need to modify the dose descriptor to take account of differences in bioavailability. The dose descriptor has been obtained from a study in which animals were exposed for 5 days per week, 6 hours per day. It is assumed that the typical shift for occupational exposure is of 8 hours duration. As this difference in time frame for uptake is of low relevance for systemic effects, the dose descriptor is not modified to take this into account.

 

The starting point is therefore1000 mg/kg/day.

 

Step 4 – Apply assessment factors

It is now necessary to apply assessment factors to take account of the uncertainties in the data. According to the guidance document, the numerical values of these factors should be determined on the basis of the available evidence. Only when there is no information on these uncertainties, default factors should be used.

 

Interspecies differences

For systemic effects the allometric scaling factor for data from studies with rats is 4. For other interspecies differences, the default factor is 2.5. 

 

1000 mg/kg/day÷ (4 x 2.5) = 100 mg/kg/day

Intraspecies differences

The standard default for intraspecies differences to take account of differences in susceptibility within a worker population is an assessment factor of 5.

 

100 mg/kg ÷ 5 = 20 mg/kg

 

Differences in duration of exposure

The starting point derives from a study of 90 days duration. Therefore, factor 2 is applied.

20 mg/kg÷ 2 = 10 mg/kg

Dose-response relationship

Starting point was the NOAEL. Therefore factor 1 is applied.

10 mg/kg÷ 1 = 10 mg/kg

Quality of whole database and endpoint-specific issues

It is not considered necessary to apply additional assessment factors to take account of any further uncertainties.

 

10 mg/kg

 

It remains unclear whether this DNEL is sufficient conservative regarding haemolytic anaemia. Therefore a second DNEL is calculated on the basis of the naphthalene uptake by inhalation during a 8 h shift. The Indicative Occupational Exposure Limit Value (ILV) set for naphthalene which is in force up to now in several European countries (like Austria, Denmark, France, Hungary, Italy, Sweden, Switzerland, Netherlands) is 50 mg/m³or 10 ppm. Historic levels in workplace areas are assumed to have been even higher than this value. If haemolytic anaemia had occurred at historic exposure levels (50 mg/m³or higher) then it is likely that such effects would have been presented in the scientific literature. The lack of such reports gives some confidence that serious, overt haemolytic anaemia is unlikely to occur at exposures in the region of 50 mg/m³(10 ppm). A survey conducted among 12 European abrasive producers in 2010 has shown that in the last 15 years (in some cases up to 40 years) of naphthalene use in the abrasives industry at least 200 workers have been regularly exposed to naphthalene vapours and dust. Companies confirmed by statements of their company doctors that skin irritation or corrosion have never been observed although there are active systems in place to pick up health complaints and adverse reaction reports. Furthermore no other observations have been made concerning any kind of occupational health effects following exposure to naphthalene dust or vapour.However, actual workplace measurements demonstrate that after implementation of enhanced risk reduction measures in the last years, workplace concentrations have been further reduced and show that workers in the abrasives industry may be exposed to naphthalene in an 8 h workday average of 25 mg/m³.In view of the absence of reports on adverse health effects among workers in the abrasive industry and the use of naphthalene for many years in occupational and consumer settings (e.g. mothballs) and the various sources of naphthalene humans are faced in daily live (e.g. cigarette smoke, burning processes)a DNEL of 25 mg/m³(5 ppm) is used as basis for the risk characterisation for haemolytic anaemia caused by the inhalation route in workers.

 

Assuming, a respiratory volume of 10 m³per 8 h shift for a worker under light activity (in accordance with ECHA guidance on information requirements and chemical safety assessment Chapter R.8) as well as 100% adsorption via the lungs, the amount of naphthalene taken up by a worker during a 8 hours shift is calculated based on the long-term inhalation DNEL for haemolytic anaemia (25 mg/m³) as follows:

 

10 m³* 25 mg/m³= 250 mg/worker and day

 

If it is assumed that absorption of naphthalene by the dermal route is 100% and the body weight of a worker is 70 kg, a calculated dermal DNEL for haemolytic anaemia is 250 mg/day÷70 kg = 3.57 mg/kg/day.

 

Against this background, a DNEL of 3.57 mg/kg/day is suggested as a DNEL for systemic effects after repeated dermal exposure. This DNEL is lower than the respective DNEL (10 mg/kg/day) calculated from theNOAEL for systemic toxicity which was identified in a 90-day dermal route study with rats. The calculated DNEL of3.57 mg/kg/day covers systemic effects as well as haemolytic anaemia.

 

5.       DNEL Long-term systemic inhalation

 

Haemolytic anaemia has been reported in humans following accidental/deliberate ingestion and following exposure of new-born babies to bedding stored with mothballs.There is a reasonable animal toxicity database available for naphthalene. However, it is apparent that the main experimental species (rats, mice and rabbits) do not provide a suitable model for naphthalene-induced haemolytic anaemia. Due to a lack of quantitative information on the exposures producing haemolytic anaemia in humans, the nature of the dose-response relationship cannot be identified. Furthermore, it was reported that individuals who are deficient in the enzyme glucose-6-phosphate dehydrogenase are more susceptible to the haemolytic effects of naphthalene than the general population. The enzyme status of the individuals was not always given in the available case reports, which adds further uncertainty to the relevance of haemolytic anaemia for the general population.

 

In general, workers engaged in production of grinding wheels are not considered to be disproportional sensitive to naphthalene like newborns or individuals who are deficient in the enzyme glucose-6-phosphate dehydrogenase. The Indicative Occupational Exposure Limit Value (ILV) set for naphthalene which is in force up to now in several European countries (like Austria, Denmark, France, Hungary, Italy, Sweden, Switzerland, Netherlands) is 50 mg/m³or 10 ppm, and – after prior cancellation - was recently re-confirmed as TLV (threshold limit value) by the American Conference of Governmental Industrial Hygienists (ACGIH 2014).

Historical levels in workplace areas are assumed to have been even higher than this value. If haemolytic anaemia had occurred at historic exposure levels (50 mg/m³or higher) then it is likely that such effects would have been presented in the scientific literature. The lack of such reports gives some confidence that serious, overt haemolytic anaemia is unlikely to occur at exposures in the region of 50 mg/m³(10 ppm). A survey conducted among 12 European abrasive producers in 2010 has shown that in the last 15 years (in some cases up to 40 years) of naphthalene use in the abrasives industry at least 200 workers have been regularly exposed to naphthalene vapours and dust. Companies confirmed by statements of their company doctors that blood anomalies or haemolytic anaemia have never been observed, although there are active systems in place to pick up health complaints and adverse reaction reports. Furthermore, no other observations have been made concerning any kind of occupational health effects following exposure to naphthalene dust or vapour.However, actual workplace measurements demonstrate that after implementation of enhanced risk reduction measures in the last years, workplace concentrations have been further reduced and show that workers in the abrasives industry may be exposed to naphthalene in an 8 h workday average of 25 mg/m³.In view of the absence of reports on adverse health effects among workers in the abrasive industry and the use of naphthalene for many years in occupational and consumer settings (e.g. mothballs), and the various sources of naphthalene humans are faced in daily live (e.g. cigarette smoke, burning processes) a DNEL of 25 mg/m³(5 ppm) is considered to be a limit value sufficiently conservative to be protective from haemolytic anaemia caused by the inhalation route in workers.

 

6.       DNEL Long-term local dermal

There is no information available to draw conclusions regarding the irritant properties of naphthalene in humans. Data from animal studies indicate that naphthalene is only a slight skin and eye irritant insufficient to warrant classification. There is no information available on skin sensitisation in humans or respiratory sensitisation in humans or animals. In animal skin sensitisation studies, negative results were obtained in both a maximisation and a Buehler study. Naphthalene is not classified as hazardous with respect to acute local dermal effects.A survey conducted among 12 European abrasive producers in 2010 has shown that in the last 15 years (in some cases up to 40 years) of naphthalene use in the abrasives industry at least 200 workers have been regularly exposed to naphthalene vapours and dust. Companies confirmed by statements of their company doctors that skin irritation or corrosion have never been observed although there are active systems in place to pick up health complaints and adverse reaction reports. Furthermore no other observations have been made concerning any kind of occupational health effects following exposure to naphthalene dust or vapour.The use of naphthalene for many years in occupational and consumer settings (e.g. mothballs) and the absence of reports on skin irritations suggest that dermal irritation and sensitisation are not of concern for human health. Thus, in accordance with Annex I of Regulation (EC) No 1907/2006 a DNEL has not been calculated.

 

7.       DNEL Long-term local inhalation

 

With regard to the local effects (nasal olfactory effects) seen in rats following repeated exposure, it was noted that there are significant species differences in response to naphthalene. For instance, anatomical and possibly also metabolic differences between the upper respiratory tract of rats and humans mean that it remains uncertain how relevant naphthalene induced olfactory epithelium damage in rats is for human health. The NOAEL for nasal inflammation in rats due to exposure to naphthalene is below 5.24 mg/m³(1 ppm). Local effects were observed with signs of proliferative repairs in the nasal olfactory epithelium at all doses down to 5.24 mg/m³(1 ppm) in a 28 day inhalation study and, therefore, a NOAEL for such effects could not be identified.

 

However, the Indicative Limit Value (ILV) set for naphthalene which is in force up to now in several European countries (like Austria, Denmark, France, Hungary, Italy, Sweden, Switzerland, Netherlands) is 50 mg/m³or 10 ppm. Levels seen historically in the workplace are assumed to have been even higher than this value. If chronic inflammatory effects (naphthalene induced olfactory epithelium damage) had occurred at historical exposure levels (50 mg/m³or higher), then it is likely that such effects would have been presented in the scientific literature. The lack of such reports gives some confidence that naphthalene- induced olfactory epithelium damage is unlikely to occur at exposures in the region of 50 mg/m³ (10 ppm). A survey conducted among 12 European abrasive producers in 2010 has shown that in the last 15 years (in some cases up to 40 years) of naphthalene use in the abrasives industry, at least 200 workers have been regularly exposed to naphthalene vapours and dust. Companies confirmed by statements of their company doctors that naphthalene-induced inflammatory responses in nasal tissues or olfactory tissues have never been observed, although there are active systems in place to pick up health complaints and adverse reaction reports. Furthermore, no other observations have been made concerning any kind of occupational health effects following exposure to naphthalene dust or vapour. However, actual workplace measurements demonstrate that after implementation of enhanced risk reduction measures in the last years, workplace concentrations have been further reduced and show that workers in the abrasives industry may be exposed to naphthalene up to 25 mg/m³ during single working steps for a short time. In view of the use of naphthalene for many years in occupational and consumer settings (e.g. mothballs), the absence of reports that naphthalene produces respiratory irritation or sensitisation suggests that these endpoints are not of concern for human health. Against this background, a DNEL of 25 mg/m³(5 ppm) is considered to be a limit value sufficiently low to be protective for nasal or olfactory epithelium damage caused by inhalation.

 

No conclusions on carcinogenicity could be drawn from the limited information available in humans. However, the latest information (status 2010) on the mode of action of naphthalene has been compiled in an expertise by CCSG (CCSG 2012_Naphthalene_mode of action.pdf). The carcinogenic potential of naphthalene has been well investigated in animals. In a 2-year carcinogenicity study on inhalation in rats, an increase in the incidence of respiratory epithelial adenomas and olfactory epithelial neuroblastomas (a very rare tumour type) was observed even with the lowest exposure concentration of 10 ppm (50 mg/m³). In view of the negative results obtained in the in vivo genotoxicity studies, naphthalene is considered to be non-genotoxic. Taking this result into account, the tumours in the animal studies were considered to arise via a non-genotoxic mechanism and, therefore, other potential mechanisms underlying the carcinogenic response were considered. It was noted that the rat nasal tumours developed only at the sites where non-neoplastic inflammatory changes (changes such as atrophy, hyperplasia and metaplasia) also occurred. Thus, it was considered that the development of the nasal tumours in the rat was a consequence of chronic tissue injury, for which an identifiable threshold (DNEL) of 25 mg/m³ (5 ppm) exists. In view of the use of naphthalene for many years in occupational and consumer settings (e.g. mothballs) and the various sources of naphthalene humans are faced in daily life (e.g. cigarette smoke, burning processes) as well as the fact that the observed type of tumour is very rare in humans suggest that carcinogenicity following respiratory irritation is unlikely to be of concern for workers health. Against this background, a DNEL of 25 mg/m³(5 ppm) is considered to be a limit value sufficiently low to be protective for nasal or olfactory epithelium damage and thus for carcinogenicity caused by the inhalation route.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

By inhalation

DNEL related information

DNEL derivation method:

other: not applicable

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

acute toxicity

Route of original study:

By inhalation

DNEL related information

DNEL derivation method:

other: not applicable

Local effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: not applicable

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

other: not applicable

General Population - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Dermal

DNEL related information

DNEL derivation method:

other: not applicable

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

acute toxicity

Route of original study:

Dermal

DNEL related information

DNEL derivation method:

other: not applicable

Local effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

skin irritation/corrosion

DNEL related information

DNEL derivation method:

other: not applicable

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

skin irritation/corrosion

DNEL related information

DNEL derivation method:

other: not applicable

General Population - Hazard via oral route

Systemic effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

repeated dose toxicity

Route of original study:

Oral

DNEL related information

DNEL derivation method:

other: not applicable

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

Most sensitive endpoint:

acute toxicity

Route of original study:

Oral

DNEL related information

DNEL derivation method:

other: not applicable

General Population - Hazard for the eyes

Local effects

Hazard assessment conclusion:

no hazard identified

Additional information - General Population

Naphthalene is not used in consumer products but only used as processing agent or for the production of grinding wheels. The use as processing agent and the production of grinding wheels take place at industrial sites with no releases to the environment. Naphthalene is only used in closed systems or in production processes with adequate systems to prevent releases to the environment via waste water or air. There are waste water treatment measures in place to prevent naphthalene release with water from cleaning processes and after burning is used to remove naphthalene from exhaust gas. Therefore, the general population is not exposed to naphthalene as a result of the use of naphthalene in industry either by direct exposure or from indirect exposure through the environment (water or food).