Residues (petroleum), steam-cracked light

Endpoint summary

Description of key information

Available data for 4 specific streams within this category [Carbon Black Oil (CAS 64742-90-1), E000014200 (CAS 68475-80-9), Rohnaphthalin-Gemisch (CAS 85117-10-8), Quenchoel (CAS 98072-36-7)], further information included in the Category Summary for Fuel Oils Category (ACC, 2005), and on specific components (benzene, toluene, ethylbenzene, styrene, naphthalene, biphenyl and anthracene) that are present in some streams indicate that acute toxicity is expected to be low. Naphthalene has been shown to be acutely toxic (producing haemolytic anaemia) in humans following oral exposure and ethylbenzene and styrene are hazardous following acute inhalation exposure. Therefore, classification will be required for streams containing a high proportion of naphthalene (≥25%) and styrene (>12.5%) but the highest concentration of ethylbenzene (10%) is too low to trigger classification. 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 classification (R67/H336) will be required for streams containing ≥20% toluene.

Additional information

Non-human information

Acute oral toxicity data on the streams Carbon Black Oil (CAS 64742-90-1), Rohnaphthalin-Gemisch (CAS 85117-10-8) and Quenchoel (CAS 98072-36-7) indicate oral LD50 values in rats of > 2000 mg/kg. E000014200 (CAS 68475-80-9) had an oral LD50 value of < 5000 mg/kg. Acute inhalation toxicity on the streams Rohnaphthalin-Gemisch (CAS 85117-10-8) and Quenchoel (CAS 98072-36-7) showed no acute inhalation toxicity at the highest achievable concentrations and acute dermal toxicity studies on the streams Carbon Black Oil (CAS 64742-90-1) and E000014200 (CAS 68475-80-9) gave acute dermal LD50 values in rats of > 2000 mg/kg. Data on the components benzene, toluene, ethylbenzene, naphthalene, biphenyl and anthracene indicate that no classification is warranted on the basis of acute lethality following exposure via oral, dermal or inhalation routes. 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 R67 under Dir 1999/45/EC and Category 3 H336 under Reg (EC) 1272/2008.

Human information

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

Data from human experiences that provide information on acute exposures 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, 2008a). 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.”

Justification for classification or non-classification

There are sufficient data on component substances to indicate that Fuel Oils streams are of low acute toxicity by the dermal and inhalation routes and do not warrant classification for these end-points under Dir 1999/45/EC or Reg (EC) 1272/2008.

Naphthalene is acutely toxic in humans producing haemolytic anaemia. Consequently Fuel Oils streams that contain ≥25% naphthalene will justify the following classification: “Harmful if swallowed” Harmful Xn R22 under Dir 1999/45/EC and Category 4 H302 under Reg (EC) 1272/2008.

Styrene is classified as harmful following inhalation exposure. Fuel Oils 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 three possible components of Fuel Oils streams (benzene, toluene and ethylbenzene) are such that labelling is required. Fuel Oils streams that meet the physicochemical requirements for R65 or contain ≥10% benzene, toluene or ethylbenzene will require labelling 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 toluene show that dizziness and sleepiness are experienced at air levels < 20 mg/L. Therefore, Fuel Oils 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.