Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

OCTAMETHYLCYCLOTETRASILOXANE

NFPA

PRODUCT USE

Lubricant and foam control agent in cosmetics and toiletries. Intermediate

SYNONYMS

C8-H24-O4.Si4, cyclosiloxanes, polysiloxanes, cyclomethylsiloxanes, "polydimethylsiloxane
cyclic tetramer", "organosilicone fluid", silicones, "cyclotetrasiloxane, octamethyl",
cyclopolydimethylsiloxane, D4

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

EMERGENCY OVERVIEW

RISK

Harmful if swallowed.
Possible risk of impaired fertility.
Flammable.
May cause long- term adverse effects in the aquatic environment.

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  Accidental ingestion of the material may be harmful; animal experiments indicate that ingestion of less than 150 gram may be fatal or may produce serious damage to the health of the individual.  

EYE

  Limited evidence or practical experience suggests, that the material may cause eye irritation in a substantial number of individuals. Prolonged eye contact may cause inflammation characterized by a temporary redness of the conjunctiva (similar to windburn).  

SKIN

  There is some evidence to suggest that the material may cause mild but significant inflammation of the skin either following direct contact or after a delay of some time. Repeated exposure can cause contact dermatitis which is characterized by redness, swelling and blistering.  Entry into the blood-stream, through, for example, cuts, abrasions or lesions, may produce systemic injury with harmful effects. Examine the skin prior to the use of the material and ensure that any external damage is suitably protected.  

INHALED

  The material is not thought to produce either adverse health effects or irritation of the respiratory tract following inhalation (as classified using animal models). Nevertheless, adverse effects have been produced following exposure of animals by at least one other route and good hygiene practice requires that exposure be kept to a minimum and that suitable control measures be used in an occupational setting.  

CHRONIC HEALTH EFFECTS

  Ample evidence from experiments exists that there is a suspicionthis material directly reduces fertility.  On the weight of evidence an important effect of octamethylcyclotetrasiloxane (OMCT) exposure is impaired fertility. The liver as a target organ for OMCT exposures. The critical effect level for repeated-dose toxicity via inhalation is considered to be 420 mg/m3, based not only on increased liver weights, but also on effects observed in other organs (adrenals, thymus, lungs) in a three-month rat inhalation study. Comparison of the critical effect level for repeated dose effects via inhalation (420 mg/m3) and the conservative upper-bounding exposure estimate via inhalation for OMCT results in an adequate margin of exposure. The critical effect level for repeated-dose toxicity via the oral route is considered to be 100 mg/kg-bw/day, based on decreased serum oestradiol in 7-  day mouse studies and decreased body-weights and relative liver weights in foetuses in 8-  day rat studies (OMCT administered to pregnant females). Comparison of the critical effect level for repeated dose effects via the oral route (100 mg/kg-bw/day) and the upper-bounding estimate of daily intake of OMCT by the general population results in an adequate margin of exposure.  Rodents given 1600 mg/kg/day of the substance over 14 days, by oral gavage, were found to have increased liver weights. An increased number of liver cells were found to be abnormal (hepatocellular  hyperplasia) In inhalation studies female rodents exposed to 300 ppm for 90 days (5 day week) were found to increase liver and ovary weights. Examination of liver and ovary cells did not reveal any abnormal  pathology. This result could not be reproduced in rabbits or guinea pigs. [GE Silicones]*  In developmental toxicity studies in which rats and rabbits were exposed to 700 ppm and 500 ppm respectively, no teratogenic effects were observed. The material has the potential to affect certain reproductive parameters (decrease in implantation sites, live litter size and viability) in laboratory animals exposed to vapour concentrations of 700 ppm or greater. The significance of these findings to humans is not known. [Dow Corning]  Range finding reproductive studies were conducted (whole body inhalation, 70 days prior to mating, through mating, gestation and lactation). Rats were exposed at 70 and 700 ppm. In the 700 ppm group, there was a  statistically significant reduction in mean litter size and in implantation sites. No product-related clinical signs were seen in the pups and no exposure related pathology was identified.  Interim results from a a 2-generation reproductive study in rats exposed to 500 and 700 ppm product (whole body inhalation, 70 days prior to mating, gestation and lactation) produced a significant decrease in live mean litter size as well as extended periods of off-spring delivery (dystocia). These results were not seen at 70 or 300 ppm dosing levels. *[GE Silicones].