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Effects on fertility

Description of key information
No other studies are available 
Link to relevant study records

Referenceopen allclose all

Endpoint:
toxicity to reproduction
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
other:
Reproductive effects observed:
not specified
Endpoint:
one-generation reproductive toxicity
Remarks:
based on generations indicated in Effect levels (migrated information)
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant (minor exception detailed below), guideline study, available as unpublished report, no restrictions, fully adequate for assessment.
Reason / purpose for cross-reference:
reference to same study
Qualifier:
according to guideline
Guideline:
OECD Guideline 422 (Combined Repeated Dose Toxicity Study with the Reproduction / Developmental Toxicity Screening Test)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: EPA OPPTS 870.3650
Deviations:
no
GLP compliance:
yes
Remarks:
GLP deviation: no lot number available of test material
Limit test:
no
Species:
rat
Strain:
other: Sprague-Dawley CD
Sex:
male/female
Details on test animals or test system and environmental conditions:
- Species: Albino rats (Outbred) VAF/Plus®, Sprague-Dawley derived (CD®), Crl:CD®(SD)IGS BR
- Source: Charles River Laboratories, Raleigh, North Carolina 27610, USA
- Age at study initiation: Approximately 8 weeks
- Weight at study initiation: Males mean 277 g (range 229-301 g); females mean 194 g (range 171-216 g)
- Fasting period before study: None
- Housing: Individually in stainless steel suspended cages with wire mesh floors and fronts (except for mating period when 1 male and 1 female were housed together)
- Diet: Certified Rodent diet No 5002 (PMI Nutrition International, St Louis, Missouri, USA) ad libitum
- Water: Municipal water ad libitum
- Acclimation period: Approximately 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature: 20- 22°C
- Humidity: 42-63%
- Air changes (per hr): Not reported
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 15 December 2003 To: 6 February 2004
Route of administration:
inhalation
Type of inhalation exposure (if applicable):
whole body
Vehicle:
other: air
Details on exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 1000 L glass and stainless steel whole-body exposure chamber
- Method of holding animals in test chamber: housed individually, the placement of animals in the chamber was rotated daily to ensure uniform exposure
- System of generating particulates/aerosols: the test substance was delivered from a single cylinder, through a regulator and two backpressure gauges via a flowmeter into the exposure chambers
- Time to T99: 23 minutes maximum
- Airflow rate: 204 Lpm
- Temperature and humidity in chamber: 21-25°C, 52-59%
- Oxygen level: at least 19%
- Air flow rate: minimum flow rate of 200 L/minute
- Air change rate: final airflow set to provide at least one air change in 5 mins (12 air changes/hour)
- Method of particle size determination: yes; weekly
- Treatment of exhaust air: filtered through a system which consisted of a coarse filter, a HEPA filter and an activated charcoal bed

TEST ATMOSPHERE
- Brief description of analytical method used: Infrared spectrophotometer (IR) 4 times per chamber per day
- Samples taken from breathing zone: yes
Details on mating procedure:
- M/F ratio per cage: 1:1
- Length of cohabitation: until evidence of mating was seen, or for two consecutive weeks
- Proof of pregnancy: vaginal plug / sperm in vaginal smear referred to as day 0 of pregnancy
- After successful mating each pregnant female was caged (how): individually in plastic "shoebox" cages with bedding
- After the mating period was over, females without evidence of copulation were removed from the mating cages, housed individually and monitored for visible signs of pregnancy with corresponding bodyweight gain.
- Any other deviations from standard protocol: no
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Exposure levels were determined using an infrared spectrophotometer 4 times/chamber/day. The test substance was evenly distributed within each chamber. The mean (± SD) analytical concentrations were 0 ± 0, 930.0 ± 27.8, 3122 ± 83 and 9148 ± 201 ppm
Duration of treatment / exposure:
Males for 2 weeks prior to mating and for an additional 28 days (minimum) after mating.
Females for 2 weeks prior to mating and gestation days 0-19.
Frequency of treatment:
6 hours/day, 7 days/week
Details on study schedule:
Females without evidence of mating that appeared to be pregnant were killed on an estimated gestation day 19.
Females that littered and their offspring were killed on post partum day 4.
Remarks:
Doses / Concentrations:
0, 900, 3000 and 9000 ppm
Basis:
other: target concentration
Remarks:
Doses / Concentrations:
0.0 ± 0.0, 930 ± 27.8, 3122 ± 83, 9148 ± 201 ppm
Basis:
analytical conc.
No. of animals per sex per dose:
12
Control animals:
yes, sham-exposed
Parental animals: Observations and examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: twice daily (mortality and clinical condition)

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: - Time schedule: Male rats were examined prior to randomisation and once weekly throughout the study. Female rats were examined prior to randomisation and once weekly throughout the premating period and on gestation days 0, 7, 14, 20 and lactation days 0 (except if parturition was not completed on the same day), 1 and 4.

BODY WEIGHT: Yes
- Time schedule for examinations: Male rats were weighed at randomisation and then weekly throughout the study. Females were weighed at randomisation, on the first day of exposure and twice weekly until evidence of copulation was observed, on gestation days 0, 7, 14 and 20, and on lactation days 1 and 4. Females were not fasted prior to recording terminal bodyweights.

FOOD CONSUMPTION: Yes
- Time schedule for examinations: Once weekly throughout the premating period. For pregnant or confirmed mated females, food consumption was recorded on gestation days 0-7, 7-14, 14-20 and on lactation days 1-4.

WATER CONSUMPTION: No

OPHTHALMOSCOPIC EXAMINATION: No

Oestrous cyclicity (parental animals):
No
Sperm parameters (parental animals):
During the microscopic examination of the testes, special emphasis was placed on the stages of spermatogenesis and the histopathology of interstitial testicular cell structure.
Litter observations:
Not applicable
Postmortem examinations (parental animals):
SACRIFICE
- Male animals: All surviving animals (after a minimum of 28 days post-mating).
- Maternal animals: All surviving animals (28 days post-mating).

GROSS NECROPSY: Yes (all animals).
- Tissues examined: adrenal glands, bone (sternum/femur), bone marrow, brain (medulla/pons, cerebrum and cerebellum), epididymides, heart, kidneys, caecum, colon, rectum, larynx, liver, lungs (with mainstem bronchi), lymph nodes (mesenteric and mediastinal), mammary glands (with adjacent skin), nasopharynx, ovaries (with oviducts), prostate, seminal vesicles, duodenum, ileum, jejunum, spinal cord (cervical, thoracic and lumbar), spleen, stomach, testes, thymus, thyroid with parathyroids, tibial nerve, trachea, urinary bladder, uterus with vagina and all macroscopic lesions and tissue masses.

ORGAN WEIGHTS: Yes. Adrenal glands, brain, epididymides, heart, kidneys, liver, lungs, ovaries, spleen, testes, thymus and uterus with vagina.

HISTOPATHOLOGY: Yes (male and female main study only).
- tissues examined: adrenal glands, bone (sternum/femur), brain (cerebellum, cerebrum and cerebellum), epididymes, heart, kidneys, large intestine (caecum, colon and rectum), liver, lungs (with mainstream bronchi), lymph node (mesenteric), lymph node (mediastinal), mammary glands (with adjacent skin), ovaries (with oviducts), prostate, seminal vesicles, small intestine (duodenum, ileum and jejunum), spinal cord (cervical, thoracic and lumbar), spleen, stomach, testes, thymus, thyroids with parathyroids, tibial nerve, trachea, urinary bladder, uterus with vagina, all macroscopic lesions and tissue masses.
Postmortem examinations (offspring):
Macroscopic postmortem examinations (external only) were performed on all surviving F1 pups on lactation day 4.
Statistics:
Group mean values of parameters for all the exposure groups were compared to the control group mean values at each time interval, using appropriate statistical methods.
Reproductive indices:
Male and female mating indices, pregnancy rates, male and female fertility indices, gestation indices and the incidence of dams with no viable pups, were analysed statistically.
Offspring viability indices:
Live birth index, litter survival and mean pup survival indices (days 0 and 4) were analysed statistically.
Clinical signs:
no effects observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Organ weight findings including organ / body weight ratios:
no effects observed
Histopathological findings: non-neoplastic:
no effects observed
Reproductive performance:
effects observed, treatment-related
CLINICAL SIGNS AND MORTALITY (PARENTAL ANIMALS).
- There was a low incidence of transient red nasal discharge between test days 8 and 29 in all groups including control.

REPRODUCTIVE PERFORMANCE (PARENTAL ANIMALS)
- Almost all mated females were found pregnant and delivered live pups; one each in the 900 and 3000 ppm groups and three in the 9000 ppm group (25%) were not pregnant. None of the differences were statistically significant. The mating index for the male rats was compared to control. Mating and gestation indices for females were comparable to control. Almost all females mated at the first opportunity. There were no treatment-related differences in the other reproductive parameters up to time of parturition, including percentange of females completing delivery and duration of gestation.
- There was a dose-related increase in post-implantation loss (as defined by the difference between the number of live pups born and the number of implantations, including any stillborn pups) in 9000 ppm females. Otherwise, there were no treatment-related differences in other parturition parameters including pre-implantation loss, the total number of pups delivered, the number of pups dying, the viability (day 4 survival) index, the pup sex ratio and the number of live pups per litter, compared to control. There were no microscopic findings considered to be treatment-related.
Dose descriptor:
NOAEC
Remarks:
systemic effects
Effect level:
9 000 other: ppm (21,394 mg/m3)
Sex:
male/female
Basis for effect level:
other: no treatment-related effects at the highest concentration tested
Dose descriptor:
NOAEC
Remarks:
Fertility
Effect level:
3 000 other: ppm (7131 mg/m3)
Sex:
male/female
Basis for effect level:
other: see 'Remark'
Dose descriptor:
NOAEC
Remarks:
Reproductive endpoints
Effect level:
3 000 other: ppm (7131 mg/m3)
Sex:
male/female
Basis for effect level:
other: see 'Remark'
Clinical signs:
no effects observed
Mortality / viability:
no mortality observed
Body weight and weight changes:
no effects observed
Sexual maturation:
not examined
Organ weight findings including organ / body weight ratios:
not examined
Gross pathological findings:
no effects observed
Histopathological findings:
not examined
There were no effects on numbers of live or dead pups, pup abnormalities, sex or weight.
Dose descriptor:
NOAEC
Remarks:
developmental effects
Generation:
F1
Effect level:
9 000 other: ppm (21,394 mg/m3)
Sex:
male/female
Basis for effect level:
other: no treatment-related effects on survival, body weight and development up to postnatal day 4 at the highest concentration tested
Reproductive effects observed:
not specified

Table 1. Delivery and litter data for rats exposed to isobutane in this study

 

control

900 ppm

3000 ppm

9000 ppm

No. Corpora lutea

16.3

15.1

14.9

16.4

No. implantation sites

14.6

14.1

13.9

15.1

Pre-implantation loss

(no. corpora lutea minus no. implantation sites)

1.8

1.0

1.0

1.3

No. pups per litter

13.8

13.5

13.2

13.4

Post-implantation loss

(no. implantation sites minus no. pups per litter)

0.8

0.6

0.7

1.8*

* Statistically significant (P<0.05)

Conclusions:
Isobutane was tested in an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen. There was no systemic toxicity, no effects on mating, gestation indices and no effects on pup endpoints. The NOAEC for these endpoints was 9,000 ppm (21,394 mg/m3). Equivocal effects at 9000 ppm on both fertility and increased post-implantation loss led to the NOAEC for fertility and reproductive endpoints being concluded to be 3000 ppm (7131 mg/m3).
Executive summary:
Rats were exposed to isobutane by inhalation (900, 3000 and 9000 ppm) in an OECD Guideline 422 combined repeated-exposure toxicity study with the reproduction/developmental screening test. Males and females were exposed for 6 hours/day, 7 days/week for 2 weeks prior to mating. Main study females were evaluated for subchronic effects and were exposed for 28 days. A satellite group of females was evaluated for reproductive effects only - exposed for at least two weeks prior to mating initiation, then during mating and gestation (days 0-19). Main study male rats were exposed during the mating and post-mating periods until euthanized for a minimum exposure of 28 days.

Exposure of male and female rats for 4-6 weeks resulted in no general systemic or neurotoxic effects. A NOAEC of 9000 ppm (21,394 mg/m3) was determined for all general systemic/neurotoxic endpoints in this study. The NOAEC for pup endpoints was also 9000 ppm (21,394 mg/m3) based on no effects on survival, body weight and development up to postnatal day 4.

Almost all mated female animals were found pregnant and delivered live pups. In the 9000 ppm group, 25% of the mated females did not become pregnant, and this reduction in the male and fertility indices (75%) was considered to be exposure-related even though it was not statistically significant. The NOAEC for fertility was therefore concluded to be 3000 ppm (7131 mg/m3). This effect is considered to be equivocal - small group sizes (12) were employed in the study and the differences reported between the control and high dose-exposed animals were small. There was also no evidence of a gradation of response, which might have been expected, where some females were not pregnant and others had a reduced number of implantations if this effect had been treatment related. The lower pregnancy rate may therefore have been a chance occurrence. Mating indices for the male rats treated with the isobutane were comparable to controls. Mating and gestation indices for the female rats treated with isobutane were also comparable to controls. There were also no treatment-related differences in the other reproductive parameters up to the time of parturition including the percent of females completing delivery and the duration of gestation, compared to controls. The 75% of females in this study becoming pregnant was also near historical control levels (87.5-100% with a mean of 93.7% in studies conducted between 2001 and 2002).

An exposure-related increase in post-implantation loss was noted for the 9000 ppm group and the NOAEC for reproductive endpoints was also concluded to be 3000 ppm (7131 mg/m3). This effect is also considered to be equivocal. There were no exposure-related differences in any of the parturition parameters including pre-implantation loss, the total number of pups delivered, the number of pups dying, the viability (4 day survival) index, the pup sex ratio and the number of live pups/litter, when compared to control. There were no exposure-related differences in body weights, weight gains or macroscopic differences in the pups at post-natal day 4.The mean number of corpora lutea were similar in both groups whilst the control group was less successful in achieving implantation and therefore had a higher pre-implantation loss than the test group. Both groups give birth to a similar number of pups per litter and therefore the treated group had a higher post-implantation loss than the control group. As both groups had the same potential number of implantations and both gave birth to a similar number of pups there is no indication of any adverse effect of isobutane on embryo/foetal survival. The apparent effect on post-implantation loss is therefore a numerical difference in this calculated parameter whilst the measured parameters showed no effect.

Effect on fertility: via oral route
Endpoint conclusion:
no study available
Effect on fertility: via inhalation route
Endpoint conclusion:
adverse effect observed
Dose descriptor:
NOAEC
7 131 mg/m³
Study duration:
subchronic
Species:
rat
Quality of whole database:
Adequate for assessment
Effect on fertility: via dermal route
Endpoint conclusion:
no study available
Additional information

Reproductive toxicity data are available for one category stream member, the C2-C4 alkanes and propene.

 

Members and constituents of the Other Petroleum Gases category are flammable gases at room temperature and therefore exposure via the dermal or oral routes is unlikely and the requirement to test is waived in accordance with REACH Annex XI.

 

Liquefied Petroleum Gas

HLS (2009) exposed groups of rats to target concentrations of 0; 1,000; 5,000; or 10,000 ppm liquefied petroleum gas (propane and propylene 93.513%) for 6 hours per day, 5 days per week, for 13 weeks. No treatment-related effect on estrous cycle in females or sperm count, motility, or morphology in males was observed at any exposure concentration. The experimentally defined NOAEC is 10,000 ppm.

 

Methane CAS Number 74-82-8

No reproductive toxicity data are available specifically for methane.

 

Ethane CAS Number 74-84-0

HLS (2010) report an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen in rats. No effects on mating, fertility, or gestation indices or reproductive performance were observed in a 6-week study in which 0, 1,600, 5,000, or 16,000 ppm ethane was administered to male and female rats by inhalation. The experimentally defined NOAEC is 16,000 ppm (19678 mg/m3).

 

Propane CAS Number 74-98-6

In male and female rats exposed to 0, 1,200, 4,000, or 12,000 ppm propane by inhalation for 6 weeks (OECD Guideline 422), no effects on mating, fertility, or gestation indices or reproductive performance were observed. The experimentally defined NOAEC is 12,000 ppm (21641 mg/m3) (HLS 2009).

 

Isobutane CAS Number 75-28-5

There were no effects on mating, gestation indices or pup endpoints (survival, body weight and development up to postnatal day 4) when isobutane was tested in an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen (HLS, 2010). Rats were exposed by inhalation for up to 6 weeks to 0, 900, 3,000, or 9,000 ppm isobutane. The NOAEC was 3000 ppm (7131 mg/m3), based on equivocal effects at 9000 ppm (21,394 mg/m3), on both fertility and post-implantation loss.

Nine out of 12 female rats exposed to 9000 ppm isobutane became pregnant following successful mating, a difference that was not significantly different from the controls (75% of females became pregnant compared with 100% of controls), and of the 9000 ppm exposed rats that became pregnant a statistically significant increase in post-implantation losses was recorded (1.8 per litter compared to 0.8 in controls). A detailed review of the study report supports the possibility that the lower pregnancy rate may have been a chance occurrence on the basis that the group size was small (12 animals per group) and the percentage of females becoming pregnant was near historical levels (75% compared with a historic range of 87.5-100% with a mean of 93.7% in studies conducted between 2001 and 2002). The mean number of corpora lutea, implantation sites, pre-implantation losses, live pups per litter, pup survival to post-natal day 4, and pup sex ratio were not significantly different, all further evidence that a real effect on fertility is questionable. The limitations of this study should be taken into account when considering the potential hazard posed by isobutane. The weight of evidence from the other C1- C4 petroleum gases, where no effects on fertility or reproduction were seen, also supports the likely lack of effect of isobutane.

 

Butane CAS Number 106-97-8

HLS (2008) report an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen in rats. No effects on mating, fertility, or gestation indices or reproductive performance were observed in a 6-week study in which 0, 900, 3,000, or 9,000 ppm butane was administered to male and female rats by inhalation. The experimentally defined NOAEC is 9,000 ppm (21394 mg/m3).

 

Propene CAS Number 115-07-1

Overall, there is a considerable amount of data from well conducted and reported guideline studies with adequate and reliable coverage of key parameters for the assessment of the reproductive toxicity potential of propene. A weight of evidence evaluation for propene and its proximate metabolite, propene oxide indicate that there is no evidence for adverse reproductive effects (including fertility). Findings include; no effects in reproductive tissues in repeated dose studies of up to 2 years on propene (NTP, 1985), no reproduction effects in a reproduction screening study (OECD 422) with propene oxide (Okuda, 2006) and no reproduction effects in a 2-generation reproduction study (OECD 416) with propene oxide (Hayes, 1988).

 

 

Summary

No quantitative data were located on the effects on fertility and reproductive parameters of Other Petroleum Gases in humans. There are no 2-generation reproduction studies available but there is sufficient weight of evidence from the component substances to conclude that further testing is scientifically unjustified (Annex XI adaptation). Inhalation exposure is the most relevant route, and a GLP-compliant guideline study is available on one category stream, the major components being propane and propylene (93.513%). In a 90 day study on liquefied petroleum gas, parameters such as sperm analysis, oestrus cycle analysis and histopathology were included (although mating was not carried out); there were no effects with a no observed adverse effect level (NOAEC) of 10,000 ppm, the maximum dose level tested.

GLP-compliant guideline studies (OECD 422) are available in animals for C2 – C4 alkanes up to 6 weeks in duration that indicate members of this category have low potential for reproductive toxicity (including effects on fertility). No biologically significant treatment-related reproductive toxicity or effects on reproductive endpoints in repeat dosing studies were observed in rats after inhalational exposure to butane, isobutane, propane or ethane. The NOAEC for fertility is 3000 ppm (7131 mg/m³) based on the study on isobutane where equivocal effects on fertility occurred at 9000 ppm (21,394 mg/m3). The limitations of this study, together with the weight of evidence from the other C2 – C4 petroleum gases support an absence of hazard for effects on fertility.

 

A more extensive database exists for main component propene which similarly supports a conclusion of low potential for reproductive toxicity/fertility effects.


Short description of key information:
The weight of evidence from studies on one category stream member and main components C2-C4 alkanes and propene indicates no evidence of reproductive toxicity.

Justification for selection of Effect on fertility via oral route:
These streams are gases at room temperature, hence fertility testing via the oral route is not technically feasible.

Justification for selection of Effect on fertility via inhalation route:
Results from an OECD 422 study on iso-butane provide a NOAEC of 7131 mg/m3 for possible effects on fertility, based on an equivocal effects at 21,394 mg/m3; this is considered a conservative conclusion as the effects seen were relatively minor in nature and not statistically significant. Supporting information regarding an absence of a potential to adversely affect fertility is provided by screening studies on ethane, propane and butane.

Justification for selection of Effect on fertility via dermal route:
These streams are gases at room temperature, hence fertility testing via the dermal route is not technically feasible.

Effects on developmental toxicity

Description of key information
The weight of evidence from studies on liquefied petroleum gas, main components C1-C4 alkanes and propene indicates no evidence of development toxicity. However, category stream members may contain carbon monoxide which could trigger classification for developmental effects.
Link to relevant study records
Reference
Endpoint:
developmental toxicity
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP compliant, guideline study, available as unpublished report, no restrictions, fully adequate for assessment
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.3700 (Prenatal Developmental Toxicity Study)
Deviations:
yes
Remarks:
The identity and stability was not in compliance with GLP regulations. The lot number was not available.
Qualifier:
according to guideline
Guideline:
OECD Guideline 414 (Prenatal Developmental Toxicity Study)
Deviations:
no
Qualifier:
according to guideline
Guideline:
other: EPA 712-C-98-207 (August 1998)
Deviations:
no
GLP compliance:
yes (incl. QA statement)
Limit test:
no
Species:
rat
Strain:
other: VAF/Plus®, Sprague-Dawley Derived (CD®) Crl:CD® IGS BR
Details on test animals or test system and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, North Carolina 27610, USA
- Age on gestation day 0: 70-84 days
- Weight on gestation day 0: 225-250 g
- Fasting period before study: none
- Housing: individually in stainless steel suspended cages with wire mesh floors and fronts
- Diet: Certified Rodent Diet, No. 5002 (PMI Nutrition International, St Louis, Missouri, USA) ad libitum except during exposures
- Water: Municipal drinking water ad libitum (except during exposures)
- Acclimation period: 4-6 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22-24°C
- Humidity: 14-60%
- Air changes: 10-15 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 22 February 2005 To: 11 March 2005
Route of administration:
inhalation: gas
Type of inhalation exposure (if applicable):
whole body
Vehicle:
other: air
Details on exposure:
TEST ANIMALS
- Source: Charles River Laboratories, Raleigh, North Carolina 27610, USA
- Age on gestation day 0: 70-84 days
- Weight on gestation day 0: 225-250 g
- Fasting period before study: none
- Housing: individually in stainless steel suspended cages with wire mesh floors and fronts
- Diet: Certified Rodent Diet, No. 5002 (PMI Nutrition International, St Louis, Missouri, USA) ad libitum except during exposures
- Water: Municipal drinking water ad libitum (except during exposures)
- Acclimation period: 4-6 days

ENVIRONMENTAL CONDITIONS
- Temperature: 22-24°C
- Humidity: 14-60%
- Air changes: 10-15 per hr
- Photoperiod: 12 hrs dark / 12 hrs light

IN-LIFE DATES: From: 22 February 2005 To: 11 March 2005
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Exposure levels analysed 4 times/chamber/day. Mean ± SD analytical concentrations were 0±0, 1013±60, 5079±217 and 10,426±527 ppm for controls, 1000, 5000 and 10,000 ppm respectively. Particle sizing indicated the atmospheres were gas/vapour only. Analysis of major components in the neat test substance and the vaporised test substance were acceptably close and the test substance was confirmed to be stable.
Details on mating procedure:
- Impregnation procedure: purchased timed pregnant
Duration of treatment / exposure:
gestation days 6-19
Frequency of treatment:
7 days/week for 6 hours/day
Duration of test:
animals received on gestation days 0, 1 or 2; experimental start (1st day of exposure) gestation day 6, terminal sacrifice gestation day 20
No. of animals per sex per dose:
24
Control animals:
other: exposed to air only
Details on study design:
- Dose selection rationale: based on a range-finding study which showed no effects at 100, 1000 or 10,000 ppm and the upper exposure concentration was less than 50% of the lower explosion limit (LEL = 2.1% = 21,000 ppm)
- Rationale for animal assignment (if not random): randomly assigned
Maternal examinations:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least twice daily
- Cage side observations checked: mortality and viability

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: out-of-chamber daily from receipt until gestation day 20. In-chamber: at least once during each exposure as a group.
- Out-of-chamber examinations comprised: general condition, skin and fur, eyes, nose, oral cavity, abdomen and external genitalia, occurrence of secretions and excretions and autonomic activity (lachrymation, piloerection, pupil size, unusual respiratory pattern), changes in gait, posture and response to handling as well as presence of repetitive circling or bizarre behaviour (self-mutilation, walking backwards).

BODY WEIGHT: Yes
- Time schedule: gestation days 3, 6, 9, 12, 15, 18 and 20

FOOD CONSUMPTION: Yes
- Time schedule: gestation days 3-6, 6-9, 9-12, 12-15, 15-18 and 18-20

POST-MORTEM EXAMINATIONS: Yes
- Sacrifice on gestation day 20
- Organs examined: Intact uteri (ovaries attached) were removed from the abdominal cavity. The gravid uteri, including the cervix, were weighed. Corpora lutea were counted and the number per ovary recorded. The number and location of the following were recorded for each uterine horn: live foetuses, late embryo-foetal deaths, early embryonic deaths. Each placenta was examined macroscopically.
Ovaries and uterine content:
The ovaries and uterine content was examined after termination: Yes
Examinations included:
- Gravid uterus weight: Yes
- Number of corpora lutea: Yes
- Number of implantations: Yes
- Number of early resorptions: Yes
- Number of late resorptions: Yes
Fetal examinations:
- External examinations: Yes: all per litter
- Soft tissue examinations: Yes: half per litter
- Skeletal examinations: Yes: half per litter
- Head examinations: Yes: half per litter
Statistics:
Continuous maternal parameters, % pre-implantation loss and % total resorptions/implant sites: If Bartlett's test significant at 1% level, a Kruskal-Wallis test and if significant at 5% level, Steel's test. If Bartlett's test not significant at 1% level, one-way analysis of variance and if significant at 5% level Dunnett's test.
Litter size: analysed using a generalised linear model. If significant, compared using pairwise tests on the least squares means.
Corpora lutea, number of implant sites, early, late and total resorptions, numbers of males and females: as for litter size except the means were adjusted for litter size.
Foetal bodyweight: mixed model of variance with dose group and foetal sex and their interaction as explanatory variables and litter size as covariate. If significant at 5% level, Dunnett's test.
Details on maternal toxic effects:
Maternal toxic effects:no effects
Dose descriptor:
NOAEC
Effect level:
10 426 ppm (analytical)
Basis for effect level:
other: maternal toxicity
Details on embryotoxic / teratogenic effects:
Embryotoxic / teratogenic effects:no effects
Dose descriptor:
NOAEC
Effect level:
10 426 ppm (analytical)
Sex:
male/female
Basis for effect level:
other: Developmental Toxicity
Abnormalities:
no effects observed
Developmental effects observed:
no

There were no effects on maternal survival, clinical observations, body weight or food consumption. There were no effects on corpora lutea numbers, pre- or post-implantation loss, litter size or gravid uterus weight. There were no effects on foetal bodyweights, foetal variants or abnormalities or on the state of ossification of the foetal skeleton.

Conclusions:
The no observed adverse effect concentration (NOAEC) of liquified petroleum gas for maternal and developmental toxicity to rats was 10,000 ppm.
Executive summary:

Exposure of pregnant rats to target concentrations of 1000, 5000 or 10,000 ppm liquified petroleum gas by whole-body inhalation on gestation days 6 -19 resulted in no effects of exposure. Therefore, a no observed adverse effect concentration (NOAEC) for maternal toxicity and developmental toxicity of 10,000 ppm was indicated.

Effect on developmental toxicity: via oral route
Endpoint conclusion:
no study available
Effect on developmental toxicity: via inhalation route
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEC
17 200 mg/m³
Study duration:
subchronic
Species:
rat
Quality of whole database:
Adequate for assessment
Effect on developmental toxicity: via dermal route
Endpoint conclusion:
no study available
Additional information

Human data

Two cases are reported of butane exposure in pregnant women, one accidentally exposed in pregnancy week 27, the other intentionally as a suicide attempt in week 30 (Health Council of the Netherlands, 2004).The first woman gave birth to a child with hydranencephaly, while the second woman gave birth to a child that died after 11 hours with severe encephalomalacia and hypoplastic kidneys. In both cases, the brain effects were not considered to be caused by butane but by intrauterine anoxia. In neither of these cases were estimations of the concentrations inhaled made, also, as the history prior to the exposures is unknown, the relationship of the developmental outcomes to butane exposure this study is highly uncertain.

 

Non human data

Liquefied Petroleum Gas

Liquified petroleum gas (propane and propylene 93.513%) was tested in an OECD Guideline 414 Prenatal Developmental Toxicity Study (HLS 2010). Exposure of pregnant rats to target concentrations of 1000, 5000 or 10,000 ppm liquified petroleum gas by whole-body inhalation on gestation days 6 -19 resulted in no effects of exposure. Therefore, a no observed adverse effect concentration (NOAEC) for maternal toxicity and developmental toxicity of 10,000 ppm was indicated.

 

Methane CAS Number 74-82-8

No developmental toxicity data are available specifically for methane.

 

Ethane CAS Number 74-84-0

HLS (2010) report an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen in rats. There were no effects on offspring survival (to postnatal day 4), pup body weight, or macroscopic post mortem evaluations in a 6 week study to GLP in which rats were exposed by inhalation prior to mating, during mating, and after mating. The experimentally defined NOAEC is 16,000 ppm (19678 mg/m3), the maximum dose tested.

 

Propane CAS Number 74-98-6

In male and female rats exposed to 0, 1,200, 4,000, or 12,000 ppm propane by inhalation for 6 weeks (OECD Guideline 422), prior to mating, during mating, and after mating, no effects on offspring survival (to post natal day 4), pup body weight, or macroscopic post mortem evaluations were observed. The experimentally defined NOAEC is 12,000 ppm (21641 mg/m3) (HLS 2009).

 

Isobutane CAS Number 75-28-5

HLS (2010) report the findings of an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen in rats exposed up to 6 weeks to 0, 900, 3,000, or 9,000 ppm isobutane by inhalation prior to mating, during mating, and after mating. There were no treatment-related differences in offspring survival (to post natal day 4), pup body weight, or macroscopic post-mortem evaluations. The NOAEC for pup endpoints is 9000 ppm (21394 mg/m3).

 

Butane CAS Number 106-97-8

HLS (2008) report an OECD Guideline 422 combined repeated-exposure toxicity, reproduction and neurotoxicity screen in rats. No effects on offspring survival (to post natal day 4), pup body weight, or macroscopic post mortem evaluations were observed in a 6-week study in which 0, 900, 3,000, or 9,000 ppm butane was administered to male and female rats by inhalation. The experimentally defined NOAEC is 9,000 ppm (21394 mg/m3).

 

Propene CAS Number 115-07-1

No developmental toxicity was reported when propene was tested in a rat developmental toxicity study (OECD Guideline 414) by inhalational exposure (BASF, 2002). No maternal toxicity was expressed at any concentration up to 10,000 ppm (17,200 mg/m3). There were no treatment-related influences on the gestational parameters and no signs of prenatal developmental toxicity, in particular no indications of teratogenicity. The NOAEC for prenatal developmental and maternal toxicity from inhalation exposure to propene is 10,000 ppm (17,200 m/m3), half the lower explosive limit.

 

 

Summary

No quantitative data were located on the effects on developmental parameters of petroleum gases in humans. Limited human data demonstrated birth defects in 2 pregnant women were associated with intrauterine anoxia rather than butane exposure, also as the history prior to the exposures is unknown, the relationship of the developmental outcomes to butane exposure this study is highly uncertain.

In animals, a prenatal developmental toxicity study is available on liquified petroleum gas (major components propane and propylene) by whole-body inhalation; a no observed adverse effect concentration (NOAEC) for maternal toxicity and developmental toxicity of 10,000 ppm was indicated. Current GLP-compliant guideline studies (OECD 422) are also available for C2-C4 alkanes up to 6 weeks in duration; there were no developmental malformations or evidence of foetal toxicity. Also data on the component substance propene further indicate that members of this category have low potential for developmental toxicity. Based on these data, no labelling is warranted.

However, some streams in this category may contain carbon monoxide and data on this material indicates evidence of developmental toxicity:

 

Carbon Monoxide CAS number 630-08-0

(Classification: CLP Category 1A, H360D)

The World Health Organisation published an extensive review of carbon monoxide in 1999 (WHO, 1999, updated 2004). In the human body, it reacts readily with haemoglobin to form carboxyhaemoglobin (COHb). Its toxic effects on humans are due to hypoxia, which becomes evident in organs and tissues with high oxygen consumption such as the brain, the heart, exercising skeletal muscle and the developing foetus. Carbon monoxide readily diffuses crosses the placenta and binds to foetal haemoglobin with a higher affinity than for maternal haemoglobin. Furthermore, the gas is cleared from foetal blood slower than from maternal blood, leading to the accumulation of carbon monoxide which, at steady state, may be up to 10 – 15 % higher than maternal concentrations. WHO state that maternal carbon monoxide exposures of 170–230mg/m3 (150–200 ppm), leading to approximately 15–25% carboxyhaemoglobin, can produce reductions in birth weight, cardiomegaly, delays in behavioural development and disruption in cognitive function.

 

Reference

World Health Organisation, 1999

Environmental Health Criteria 213 (Carbon Monoxide, second edition)

1999, updated 2004

 

 

 

 


Justification for selection of Effect on developmental toxicity: via oral route:
These streams are gases at room temperature, hence developmental toxicity testing via the oral route is not technically feasible.

Justification for selection of Effect on developmental toxicity: via inhalation route:
Results from an OECD 414 developmental toxicity study on liquified petroleum gas (comprising propane and propylene, 93.513%) provide no evidence of foetal toxicity at exposures up to10,000 ppm LPG (equivalent to approx. 17,200 mg/m3 propene).

Justification for selection of Effect on developmental toxicity: via dermal route:
These streams are gases at room temperature, hence developmental toxicity testing via the dermal route is not technically feasible.

Toxicity to reproduction: other studies

Additional information

No other studies are available

Justification for classification or non-classification

The weight of evidence from studies on one stream member, the main components C1-C4 alkanes and propene, indicates there is adequate information available from which to assess the potential of Other Petroleum Gases to induce reproductive or developmental effects and to conclude that classification is not warranted. However category streams containing ≥ 0.3% carbon monoxide should be classified Cat 1A H360D. 

Additional information