Appendices of the Final Screening Assessment

Petroleum Sector Stream Approach

Petroleum and Refinery Gases
[Industry-Restricted]

Chemical Abstracts Service Registry Numbers
68131-75-9
68477-33-8
68477-85-0
68527-19-5

Environment Canada
Health Canada
January 2014

Table of Contents

• Appendix 1: Petroleum substance grouping
• Appendix 2: Substance identity and physical and chemical properties of representative structures for the petroleum and refinery gases listed in this screening assessment
• Appendix 3: Measures designed to prevent, reduce or manage unintentional releases
• Appendix 4: Release estimation of industry-restricted petroleum and refinery gases during transportation
• Appendix 5: Modelling results for environmental properties of petroleum and refinery gases
• Appendix 6: Modelling results for human exposure to potential releases of petroleum and refinery gases
• Appendix 7: Summary of the toxicological effects of the component classes of petroleum and refinery gases
• Appendix 8: Summary of the critical health effects information for 1,3-butadiene
• Back to the final screening assessment

Appendix 1: Petroleum substance grouping

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Appendix 2: Substance identity and physical and chemical properties of representative structures for the petroleum and refinery gases listed in this screening assessment

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Appendix 3: Measures designed to prevent, reduce or manage unintentional releases

For the Canadian petroleum industry, requirements at the provincial/territorial level typically prevent or manage the unintentional releases of petroleum substances and streams within a facility through the use of operating permits (SENES 2009).

Additionally, existing occupational health and safety legislation specifies measures to reduce occupational exposures of employees, and some of these measures also serve to reduce unintentional releases (CanLII 2009).

Non-regulatory measures (e.g., guidelines, best practices) are also in place at petroleum sector facilities to reduce unintentional releases. Such control measures include appropriate material selection during the design and setup processes, regular inspection and maintenance of storage tanks, pipelines and other process equipment, the implementation of leak detection and repair or other equivalent programs, the use of floating roofs in above-ground storage tanks to reduce the internal gaseous zone and the minimal use of underground tanks, which can lead to undetected leaks or spills (SENES 2009).

For those substances containing highly volatile components (e.g., low boiling point naphthas, gasoline), a vapour recovery system is generally implemented or recommended at loading terminals of Canadian petroleum facilities (SENES 2009). Such a system is intended to reduce evaporative emissions during handling procedures.

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Appendix 4: Release estimation of industry-restricted petroleum and refinery gases during transportation

Generic calculation process for release quantities (leaks only) in Table 3 in the text:

For unintentional releases due to leaks (kg/leak):

MG

LOSSF × MT × VPPG

VPPG

(P/PATM) / (1 + P/PATM)

MSL

MG/NUMS

where:

MG

evaporative emission quantity to air due to leaks (kg/year)

LOSSF

loss fraction, derived from historical data on reported leaks versus transport quantities from Statistics Canada and Transport Canada

MT

transport quantities, derived from information submitted under section 71 of CEPA 1999 (Environment Canada 2009)

VPPG

percentage partitioning into air estimated by vapour pressure only (assuming that Raoult’s Law and Dalton’s Law are valid)

P

vapour pressure of the substance at the release temperature (Pa)

PATM

ambient air pressure (Pa)

MSL

evaporative emission quantity per leak event (kg/leak)

NUMS

maximum number of leaks per year, from Table A4.1

As stated in the text, the number of pipeline leaks in Alberta was extrapolated to Canada based on a proportional analysis of the number of leaks per kilometre of Alberta pipeline and the kilometres of pipeline in each province and territory, regardless of the substance that they carried. The interprovincial pipelines were not taken into account, as they have a very different leak rate per kilometre of pipeline compared with pipelines within Alberta. The leaks considered here are leaks of all petroleum substances and are not specific to petroleum and refinery gases, as there are no data specific to petroleum and refinery gases or to other similar substances.

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Appendix 5: Modelling results for environmental properties of petroleum and refinery gases

Table A5.1. Results of the Level III fugacity modelling for components of petroleum and refinery gases (EQC 2003)

Release of substance to each compartment (100%); % of substance partitioning into each compartment

Abbreviation: n.a., not applicable.

Table A5.3. Modelled data for primary and ultimate biodegradation of representative structures for petroleum and refinery gases

Primary Degradation

Ultimate Degradation

 

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Appendix 6: Modelling results for human exposure to potential releases of petroleum and refinery gases

Table A6.2. Modelling results of dispersion profile of 1,3-butadiene from unintentional on-site releases of petroleum and refinery gases (site-restricted and industry restricted).^{Footnote Table A6.2[a].7}

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Appendix 7: Summary of the toxicological effects of the component classes of petroleum and refinery gases ^Footnote[1]

Alkanes

In humans, it has been observed that alkanes of low molecular weight (MW) (e.g., methane) can cause displacement of oxygen for acute exposures at high concentrations, which may lead to asphyxiation. At higher MWs, substances such as propane can act as mild depressants on the central nervous system (API 2001a). In experimental animals, LC₅₀ values for alkanes range from 658 mg/L (658 000 mg/m³) (butane) to greater than 800 000 ppm (1 440 000 mg/m³) (propane), depending on the substance, concentration and duration of the acute exposure (Shugaev 1969; Clark and Tinson 1982). Rats were exposed to mixtures of alkanes (50% butane / 50% pentane; 50% isobutane / 50% isopentane) via inhalation for 90 days in a study designed to investigate kidney effects; a NOEC of 4489 ppm (11 943 mg/m³) ^Footnote[2] (highest concentration tested) was identified (Aranyi et al. 1986). Negative mutagenicity results were observed for various alkanes (propane, n-butane, isobutane, n-pentane and isopentane) that were tested via the Ames assay, although toxicity was observed with three of the gases (n-pentane, isopentane and isobutane) at various concentrations (Kirwin and Thomas 1980). Butane and isobutane were classified by the European Commission on the basis of carcinogenicity when they contain 1,3-butadiene (as a refinery by-product) at a concentration greater than or equal to 0.1% by weight (European Commission 2001; ESIS 2008).

Alkenes

In experimental animals exposed by inhalation, concentrations of up to 25–70% propene and 15–40% butene induced anesthesia in rats, cats and mice (Brown 1924; Riggs 1925; Virtue 1950), whereas narcosis was noted in mice exposed to up to 70% isobutene via inhalation (Von Oettingen 1940). Acute toxicity values (LC₅₀) are noted to range from greater than 65 000 ppm (111 736 mg/m³) (propene; MW = 42.03 g/mol) to 620 mg/L (620 000 mg/m³) (isobutene) (Shugaev 1969; Conolly and Osimitz 1981).

Short-term toxicity studies show that oral exposure to isobutene results in a no-observed-adverse-effect level of 150 mg/kg body weight per day, despite the occurrence of significant biochemical changes that fall into the historical control range (Hazleton Laboratories 1986). Short-term exposure by inhalation resulted in changes to hematology in rats exposed for a few days to 60% ethene (approximately 690 000 mg/m³) (Fink 1968), as well as clinical and biochemical changes in rats exposed for 70 days to 100 ppm (115 mg/m³) ethene (MW of ethene = 28.02 g/mol) (Krasovitskaia and Maliarova 1968). Exposure to propene resulted in a lowest NOEC value of 10 000 ppm (17 190 mg/m³) for a 28-day exposure to multiple concentrations of propene (MW = 42.03 g/mol) up to 17 190 mg/m³ (DuPont 2002).

The lowest lowest-observed-effect concentration identified for subchronic toxicity is 500 ppm (1146 mg/m³) in a 14-week study in which male and female B6C3F1 mice and F344/N rats were exposed by inhalation to isobutene (MW = 56.10 g/mol) at concentrations up to 8000 ppm (18 336 mg/m³), resulting in significant increases in absolute and relative right kidney weights in female mice. In male mice, the absolute right kidney weight was increased at 1000 and 8000 ppm (2292 and 18 336 mg/m³). In female rats, there was a significant increase in relative liver weights from 500 ppm (1146 mg/m³) and in absolute liver weights from 1000 ppm (2292 mg/m³). In male rats, a significant increase in relative right kidney weight was observed from 500 ppm (1146 mg/m³), with an increase in absolute right kidney weight at 4000 ppm (9168 mg/m³) (NTP 1998). In addition, a 90-day continuous inhalation study conducted in newborn rats caused delays in coat appearance, tooth development and eye opening, as well as hypertension, inhibition of cholinesterase activity and behavioural changes, at an ethene (MW = 28.02 g/mol) concentration of 2.62 ppm (3 mg/m³) (Krasovitskaia and Maliarova 1968).

With regard to developmental toxicity, NOEC values of 5000 ppm (5750 mg/m³) for ethene (MW = 28.02 g/mol), 10 000 ppm (17 190 mg/m³) for propene (MW = 42.03 g/mol) and 5000 ppm (11 460 mg/m³) for 2-butene (MW = 54.04 g/mol) were identified in rats exposed by inhalation (Waalkens-Berendsen and Arts 1992; Aveyard 1996; BASF 2002). Effects on reproductive organs were observed in male rats exposed to isobutene via inhalation over 14 weeks; these include a significant increase in left epididymal weight and a decrease in epididymal sperm motility at 8000 ppm (18 336 mg/m³). In addition, female rats were reported to have an increased estrous length with a related decrease in diestrous length; however, the length of the estrous cycle was not noted to change (NTP 1998).

Both propene and ethene have been classified as Group 3 carcinogens (not classifiable as to its carcinogenicity to humans) by IARC (1994a,b). For propene, a 2-year inhalation study (concentrations up to 10 000 ppm [17 190 mg/m³]; MW for propene = 42.03 g/mol) showed the occurrence of hemangiosarcoma in male and female mice, as well as lung tumours (negative trend with increasing concentration) in male mice. No tumours were observed under the same protocol in rats (Quest et al. 1984; NTP 1985). A second inhalation study in mice (78 weeks) and rats (104 weeks) conducted with up to 5000 ppm (8600 mg/m³) propylene showed no differences in tumour incidence compared with controls (Ciliberti et al. 1988). For ethene, a 2-year study in rats did not result in increased tumour incidence at concentrations up to 3000 ppm (3438 mg/m³; MW of ethene = 28.02 g/mol) (Hamm et al. 1984). Chronic exposure of male and female F344 rats and B6C3F1 mice to isobutene at levels up to 8000 ppm (18 336 mg/m³; MW of isobutene = 54.04 g/mol) for 104 weeks was noted to cause an increased incidence of thyroid gland follicular cell carcinoma in male rats (NTP 1998). In addition, an increased incidence of hyaline degeneration in the nose of rats and mice was reported (NTP 1998).

Ethene, propene and 1-butene were all noted to cause an increased incidence of DNA adducts in vivo (Segerback 1983; Tornqvist et al. 1989; Filser et al. 1992; Eide et al. 1995; Wu et al. 1995; Zhao et al. 1999; Rusyn et al. 2005; Pottenger et al. 2007), but no micronuclei were induced when rats and mice were exposed to ethene, propene or isobutene (Exxon Biomedical Sciences, Inc. 1990; Vergnes and Pritts 1994; NTP 1998; Pottenger et al. 2007). When ethene, 1-butene, 2-butene or isobutene was administered in vitro, negative results were obtained for mutagenicity in bacteria (Landry and Fuerst 1968; Hamm et al. 1984; Hughes et al. 1984; Staab and Sarginson 1984; Shimizu et al. 1985; Victorin and Stahlberg 1988; Thompson 1992; Wagner et al. 1992; Araki et al. 1994; NTP 1998; JETOC 2000), mouse lymphoma cells with and without activation (Staab and Sarginson 1984), micronuclei induction without activation (Jorritsma et al. 1995), chromosomal aberrations with and without activation (Riley 1996; Wright 1992) and cell transformation with and without activation (Staab and Sarginson 1984).

Other Components

The refinery gases (as part of the American Petroleum Institute grouping of petroleum gases) are noted to contain alkadienes, alkynes, aromatics, inorganics and mercaptans in addition to alkanes and alkenes, although as less abundant components in the petroleum stream (API 2001a). Many of these components are described below.

Alkadienes

As noted in the health effects section of the screening assessment, a member of the alkadienes, 1,3-butadiene, is classified as both a carcinogen and a mutagen by several national and international agencies (Canada 2000b; EURAR 2002; U.S. EPA 2002; IARC 2008; NTP 2011a). A thorough review of the human health effects of 1,3-butadiene was previously done under the second Priority Substances List (Canada 2000b). 1,3-Butadiene was subsequently added to the List of Toxic Substances on Schedule 1 of CEPA 1999. Alkadienes have been observed to have narcotic properties at high concentrations and low general toxicity (Sandmeyer 1981).

Another member of the alkadienes, 2-methyl-1,3-butadiene or isoprene, is also classified as a carcinogen (Group 2B: possibly carcinogenic to humans [IARC 1999]; Category 2: suspected human carcinogen, may cause cancer [European Commission 2004] and “reasonably anticipated to be a human carcinogen” [NTP 2011b]), as well as a mutagen (European Commission 2004; ESIS 2008). Isoprene is noted to have reproductive effects in mice (testicular atrophy, similar to that observed after 1,3-butadiene exposure), as well as developmental effects (reduced fetal body weight, increased incidence of supernumerary ribs) (Mast et al. 1989, 1990). As well, isoprene has been reported to have effects on mortality, body weight, organ weights, hematology and histopathology (stomach hyperplasia, olfactory degeneration, thymic atrophy, hepatocellular foci changes, alveolar hyperplasia, spinal cord degeneration) in mice after short- and long-term inhalation exposures (Melnick et al. 1990, 1994, 1996). On the basis of carcinogenicity, for which there may be a probability of harm at any level of exposure, the Government of Canada concluded that isoprene should be considered as a substance that may be entering the environment in a quantity or concentration or under conditions that constitute or may constitute a danger in Canada to human life or health (Canada 2008).

Alkynes

Ethyne or acetylene is noted to be a simple asphyxiant (HSDB 2008); effects observed in humans after inhalation include intoxication, aggressiveness and unconsciousness at high concentrations (U.S. EPA 2008c). Acetylene is noted to cause increased mortality in various species of experimental animals, as well as intoxication or anesthesia. Effects in the liver (LOAEC = 266.3 mg/L [266 300 mg/m³]), kidneys and spleens of rats were observed following repeated exposure via inhalation. Genotoxic effects were not observed in vitro (U.S. EPA 2008c).

Aromatics

Benzene is noted to be a carcinogen, as classified by the Government of Canada (carcinogenic to humans; List of Toxic Substances on Schedule 1 of CEPA 1999) (Canada 1993), IARC (1987) (Group 1: carcinogenic to humans), the European Commission (Category 1 carcinogen: may cause cancer) (ESIS 2008), the US National Toxicology Program (NTP 2011c) (known human carcinogen) and the U.S. EPA (2008d) (Group A). In addition, benzene has been classified as a mutagen (Category 2: may cause heritable genetic damage) (European Commission 2004; ESIS 2008).

Inorganics

Hydrogen sulfide has been evaluated by the International Programme on Chemical Safety (IPCS) in both an Environmental Health Criteria monograph (IPCS 1981) and a Concise International Chemical Assessment Document (IPCS 2003). In addition, the US Agency for Toxic Substances and Disease Registry (ATSDR 2006) has generated a toxicological profile on hydrogen sulfide. The Government of Canada is currently assessing the potential impacts of hydrogen sulfide on human health from various uses and sources.

Ammonia has been evaluated by IPCS (1986), ATSDR (2004) and the Organisation for Economic Co-operation and Development (OECD) Screening Information Dataset (SIDS) program (OECD 2007). In addition, ammonia has been evaluated by the Government of Canada under the Priority Substances Assessment Program for its presence in the aquatic environment, where “conclusions drawn on the basis of a more robust data set on environmental effects would also be protective of human health” (Canada 2001a).

Both nitrogen and carbon dioxide have been noted to be inert pesticide ingredients by the U.S. EPA (2004b). Carbon monoxide has been classified by the European Commission as a Category 1 reproductive toxin (ESIS 2008) and has also been reviewed by IPCS (1999).

Mercaptans

Two mercaptans noted to be components of petroleum and refinery gases have been evaluated or reviewed by various international or national agencies; however, for the purposes of this assessment, an evaluation of these components will not be included.

Methanethiol or methyl mercaptan has been reviewed by ATSDR (1992) and included in a review of aliphatic and aromatic sulfides and thiols by the Joint Food and Agriculture Organization of the United Nations (FAO)/World Health Organization (WHO) Expert Committee on Food Additives (JECFA) (WHO 2000). In addition, both methanethiol and ethanethiol are substances scheduled for evaluation under the OECD SIDS program, but a final review has not been made available at this time (OECD 2000).

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Appendix 8: Summary of the critical health effects information for 1,3-butadiene