Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

HYDROCARBONS, C5-UNSATURATED

NFPA

PRODUCT USE

Monomer in the manufacture of `synthetic' rubber and butyl rubber; in the production of
synthetic elastomers; as a chemical intermediate.

SYNONYMS

isoprene

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

EMERGENCY OVERVIEW

RISK

Explosive when dry.
May form explosive peroxides.
HARMFUL - May cause lung damage if swallowed.
Highly flammable.

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  Although ingestion is not thought to produce harmful effects, the material may still be damaging to the health of the individual following ingestion, especially where pre-  existing organ (e.g. liver, kidney) damage is evident. Present definitions of harmful or toxic substances are generally based on doses producing mortality (death) rather than those producing morbidity (disease, ill-health). Gastrointestinal tract discomfort may produce nausea and vomiting. In an occupational setting however, ingestion of insignificant quantities is not thought to be cause for concern.  Considered an unlikely route of entry in commercial/industrial environments. The liquid may produce gastrointestinal discomfort and may be harmful if swallowed. Ingestion may result in nausea, pain and vomiting. Vomit entering the lungs by aspiration may cause potentially lethal chemical pneumonitis.  

EYE

  Although the material is not thought to be an irritant, direct contact with the eye may produce transient discomfort characterized by tearing or conjunctival redness (as with windburn).  The vapour and liquid both produce eye discomfort. Tearing and reddening of the eyes are symptomatic of overexposure. Higher levels of vapour are generated with increased temperature and engineering controls should be introduced when any discomfort is experienced following exposure to mists or vapour.  

SKIN

  Skin contact with the material may damage the health of the individual; systemic effects may result following absorption.  The material is not thought to be a skin irritant (as classified using animal models). Temporary discomfort, however, may result from prolonged dermal exposures. Good hygiene practice requires that exposure be kept to a minimum and that suitable gloves be used in an occupational setting.  The liquid may produce skin discomfort following prolonged contact. Defatting and/or drying of the skin may lead to dermatitis.  Open cuts, abraded or irritated skin should not be exposed to this material.  Toxic effects may result from skin absorption.  

INHALED

  Inhalation may produce health damage*.  The material is not thought to produce respiratory irritation (as classified using animal models). Nevertheless inhalation of the material, especially for prolonged periods, may produce respiratory discomfort and occasionally, distress.  Inhalation of high concentrations of gas/vapor causes lung irritation with coughing and nausea, central nervous depression with headache and dizziness, slowing of reflexes, fatigue and inco-ordination.  If exposure to highly concentrated solvent atmosphere is prolonged this may lead to narcosis, unconsciousness, even coma and possible death.  Central nervous system (CNS) depression may include general discomfort, symptoms of giddiness, headache, dizziness, nausea, anaesthetic effects, slowed reaction time, slurred speech and may progress to unconsciousness. Serious poisonings may result in respiratory depression and may be fatal.  Material is highly volatile and may quickly form a concentrated atmosphere in confined or unventilated areas. Vapor is heavier than air and may displace and replace air in breathing zone, acting as a simple asphyxiant. This may happen with little warning of overexposure.  

CHRONIC HEALTH EFFECTS

  Principal routes of exposure are by accidental skin and eye contact and by inhalation of vapors especially at higher temperatures.  Studies of employees in the Russian rubber industry showed reduced body  temperature, increased reflex time, decreased olfactory sensitivity and  physiological changes in the nervous and cardiovascular systems. These  employees were also exposed to methanol, formaldehyde, isopentane,  dimethyldioxane and toluene. Workers exposed to the structurally similar  1,3-butadiene showed a lower than expected overall mortality rate and no  elevated mortality rates for individual cancers.  Diepoxide metabolites of isoprene tested positive in a mutagenicity assay  using strains of Salmonella.  An investigation (1) to establish th effects of inhaled isoprene on rats  was conducted for 6 hours/day, 5 days/week for 13 weeks and 26 weeks.  Results showed that there were no treatment related gross or microscopic  changes in the 13-week treated rats exposed at up to 7000 ppm whilst mice  showed mid anaemia and microscopic changes in the forestomach, nasal  cavity, liver and testis. Rats exposed for 26 weeks showed severe  interstitial tissue hyperplasia at 7000 ppm. After a 26 week recovery  period, interstitial cell adenomas were slightly higher in male rats  exposed to 700 ppm or higher. Male mice exposed for 26 weeks showed more  extensive abnormalities. Survival was reduced with early deaths being due  to various neoplastic lesions. Towards the end of the exposure period,  abnormal posture and hind-limb impairment were observed but these  gradually normalised during a recovery period. Incidence of neoplasms of  the liver, lung, forestomach and Harderian gland, together with liver  adenomas were significantly higher in mice exposed at levels exceeding  700 ppm. Alveolar epithelial hyperplasia was significantly increased at  the end of a 26 week recovery period and probably represented a  pre-neoplastic change. Testicular atrophy was highest in a group of mice  exposed to 7000 ppm for 26 weeks. Spinal cord degeneration was observed  during the recovery period and probably accounted for hindlimb  dysfunction.  (1) Melick, R.L., et al: Cancer Research, 54, 20, pp 5333-5339, 1994