Distillates (petroleum), steam-cracked, C8-12 fraction

Endpoint summary

Description of key information

Available data for 4 specific streams within this category Cracked distillate [CAS 68477-40-7], C9 Resinfeed [CAS 68477-54-3], E000144700 [CAS 68516-20-1] and C9 Produkt [CAS 94733-07-0] and on specific components (benzene, toluene, 1,3-butadiene, naphthalene and isoprene) that are present in some streams indicate that acute toxicity is generally expected to be low. Resin Oil and Cyclic Dienes do not pose an acute hazard following skin contact (dermal LD50 > 2000 mg/kg). Two streams (E000044012 [CAS 68478-10-4], E000044146 [CAS 68478-10-4]) were considered to be hazardous following acute inhalation exposures. Streams containing a high proportion of naphthalene (≥25%) are expected to be hazardous following oral exposures. Naphthalene has been shown to be acutely toxic (producing haemolytic anaemia) in humans and is labelled R22. Styrene is hazardous following acute inhalation exposure and classification will be required for streams containing ≥12.5%. Following acute inhalation exposures to toluene in humans a number of subjective sensations such as headache, dizziness, feeling of intoxication, irritation and sleepiness and decreases in acute neurobehavioural performance are seen. The NOAEC for acute neurobehavioural effects in humans is 50 ppm (188 mg/m3) and labelling (R67) will be required for streams containing ≥20% toluene.

Additional information

Non-human information

Acute toxicity data are available for 6 streams:

Cracked distillate [CAS 68477-40-7]: Low toxicity was seen following exposure via the oral, dermal or inhalation (TNO, 1989a, c; TNO, 1990a) and no labelling is required.

C9 Resinfeed [CAS 68477-54 -3]: Acute oral dermal and inhalation LD50 values exceed those that trigger labelling (TNO, 1989b, d; TNO, 1990b).

E000044012 [CAS 68478-10-4]: Acute toxicity was seen following oral (LD50 < 5000 mg/kg; UBTL, 1990b) and inhalation exposure (LC50 <5.81 mg/L; UBTL, 1990f) but not dermal exposure (UBTL, 1990g).

E000044146 [CAS 68478-10-4]: Oral (LD50 < 5000 mg/kg; UBTL, 1990c) and inhalation exposure (LC50 <5.81 mg/L; UBTL, 1990e) indicated some acute toxicity. No evidence of toxicity was seen following dermal exposure (UBTL, 1990i).

E000144700 [CAS 68516-20 -1]: There was no evidence of toxicity following oral (UBTL, 1990a), dermal (UBTL, 1990h) or inhalation exposure (UBTL, 1990d).

C9 Produkt [CAS 94733-07-0]: Low acute oral (BASF, 1989) and inhalation (BASF, 1990a) toxicity was seen with LD50 > 2000mg/kg and LC50 greater than the highest dose achievable (4.74 mg/L).

Data on the components benzene, 1,3-butadiene, isoprene, toluene, naphthalene and ethylbenzene indicate that no classification is warranted on the basis of acute lethality following exposure via oral, dermal or inhalation routes. Xylenes are classified as harmful following exposure via inhalation and dermal routes, however the maximum concentration in Resin Oils and Cyclic Dienes streams is 25 % which is too low to trigger labelling under DPD (55%). Styrene is considered to be harmful following inhalation exposure and toluene produces unsteady gait and other indications of neurobehavioural activity at concentrations < 20 mg/L justifying classification. 

Human information

There are no specific studies on the oral, inhalation or dermal toxicity in humans for streams in this category.

Data from human exposures that provide information on acute exposures that are of value to the risk assessment process are available for benzene, toluene and naphthalene:

Benzene (Classification: EU – R65; GHS/CLP: Category 1, H304): Human data on oral toxicity indicate that ingestion of 15 mL (176 mg/kg bw) benzene can cause death after collapse, bronchitis and pneumonia (EU, 2008b). Exposure for 5-10 minutes to benzene vapours of 65-61 mg/L is fatal and exposure to 25 mg/L for 30 minutes is dangerous to life, while a one-hour exposure to 1.6 mg/L causes only some symptoms of illness.

Toluene (Classification: EU – R65, R67; GHS/CLP: Category 1, H304, Cat 3 H336): The acute effects of toluene inhalation exposure include headache, dizziness, feeling of intoxication, irritation and sleepiness and decreases in acute neurobehavioural performance at concentrations ≥ 75 ppm (EU, 2003a). A NOAEC of 50 ppm (188 mg/m3) can be determined for acute neurobehavioural effects in humans (Muttray et al, 2005).

Naphthalene (Classification: EU -R22; GHS/CLP - Cat 4 H302) The EU RAR (EU, 2003b) concluded “Naphthalene is of low toxicity in rats, with mice being more sensitive. It appears that rodents are not suitable animal models for the acutely toxic human health effects of naphthalene in relation to haemolytic anaemia. Thus, while the LD50 results from the rat suggest relatively low acute toxicity in this species, the available information in humans indicates significant toxicity. Very severe haemolytic anaemia occurred in one case report (of a 16 year old female) at an estimated single oral dose of approximately 6 g. It is possible that this represents a lethal dose given that a number of blood transfusions were required. ”

References

EU (2003a). European Union Risk Assessment Report for Toluene. EC Joint Research Centre http: //ecb. jrc. ec. europa. eu/DOCUMENTS/Existing- Chemicals/RISK_ASSESSMENT/REPORT/toluenereport032. pdf

EU (2003b). European Union Risk Assessment Report for Napththalene. EC Joint Research Centre. http: //ecb. jrc. ec. europa. eu/DOCUMENTS/Existing-Chemicals/RISK_ASSESSMENT/REPORT/naphthalenereport020. pdf

EU (2008b). European Union Risk Assessment Report for Benzene. EC Joint Research Centre. http: //ecb. jrc. ec. europa. eu/documents/Existing-chemicals/RISK_ASSESSMENT/REPORT/benzenereport063. pdf.

Justification for classification or non-classification

There are sufficient data on 6 streams {Cracked distillate [CAS 68477-40-7], C9 Resinfeed [CAS 68477-54-3], E000044012 [CAS 68478-10-4], E000044146 [CAS 68478-10-4], E000144700 [CAS 68516-20-1] and C9 Produkt [CAS 94733-07-0]} and on component substances to indicate that Resin Oils and Cyclic Dienes streams are of low acute toxicity by the dermal route and do not warrant classification for this end-point under Dir 1999/45/EC or Reg (EC) 1272/2008.

Two streams (E000044012 [CAS 68478-10-4], E000044146 [CAS 68478-10-4]) were considered to be hazardous following acute inhalation exposures and labelling is proposed as follows: Harmful Xn R20 “Harmful by inhalation under Dir 1999/45/EC and Category 4 H332 “Harmful if inhaled” under Reg (EC) 1272/2008.

Naphthalene is acutely toxic in humans producing haemolytic anaemia. Using the following formula for Oral Toxicity: 100/ATE_mix= ∑c_I/ATE_i and assuming the LD50 of naphthalene is 500 mg/kg (point estimate for a class 4 chemical) Resin Oils and Cyclic Dienes streams that contain ≥25% naphthalene will justify the following classification: Harmful Xn R22 “Harmful if swallowed” under Dir 1999/45/EC and Category 4 H302 under Reg (EC) 1272/2008.

Styrene is classified as harmful following inhalation exposure. Resin Oils and Cyclic Dienes streams that contain ≥12 5% styrene will justify the following classification: Harmful Xn R20 “Harmful by inhalation under Dir 1999/45/EC and Category 4 H332 “Harmful if inhaled” under Reg (EC) 1272/2008.

The viscosity and surface tension of four possible components of Resin Oils and Cyclic Dienes streams (benzene, toluene, xylenes and ethylbenzene) are such that labelling is required. Unless data for specific Resin Oils and Cyclic Dienes streams indicate that they do not meet the physicochemical requirements for R65 it is assumed that total content of benzene, toluene, xylenes and ethylbenzene is ≥ 10% and that labelling will be required as follows: harmful Xn, R65, "May cause lung damage if swallowed" under Dir 1999/45/EC and under Reg (EC) 1272/2008 "Aspiration toxicity Category 1, H304".

Data from experimental exposure of human volunteers with a toluene show that dizziness and sleepiness are experienced at air levels < 20 mg/L. Therefore, Resin Oils and Cyclic Dienes streams that contain ≥20 % toluene will justify classification R67 “Vapours may cause drowsiness” under Dir 1999/45/EC and Category 3 H336 under Reg (EC) 1272/2008.