Dichloromethyl(3,3,3-trifluoropropyl)silane

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Acute/short term exposure

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

24.5 mg/m³

Most sensitive endpoint:

skin irritation/corrosion

DNEL related information

Overall assessment factor (AF):

1

Acute/short term exposure

DNEL related information

Workers - Hazard via dermal route

Systemic effects

Acute/short term exposure

DNEL related information

Additional information - workers

There are no adequate data regarding the repeated dose toxicity of dichloromethyl(3, 3, 3-trifluoropropyl)silane or its hydrolysis product methyl(3, 3,3-trifluoropropyl)silanediol, therefore data from the other hydrolysis product HCl are considered appropriate to determine local DNELs for the parent substance. Dichloromethyl(3, 3, 3-trifluoropropyl)silane hydrolyses very rapidly in contact with moist air and in contact with tissues to form 2 moles of hydrogen chloride (HCl) and one mole of methyl(3, 3,3-trifluoropropyl)silanediol. Local effects (corrosion) are therefore influenced by the formation of HCl.

Hydrogen chloride (HCl)

An EU long-term inhalation Occupational Exposure Limit (OEL) has been set for HCl as 8 mg/m³(8 h TWA) in Commission Directive 2000/39/EC.

The SIDS Initial Assessment Report (SIAR) for HCl describes a systemic NOAEL of 20 ppm from a 90-day repeated dose inhalation study (OECD, 2002). However, since the NOAEL for local effects in the same study was 10 ppm it is considered by the author of this CSR that the observed effects at 20 ppm were secondary to corrosion.

The OECD SIAR (2002) reports the following:

For repeated dose toxicity, 13 inhalation and 7 oral dose studies has been reported. Among those, only the inhalation studies reported by CIIT (1984) were reliable. They were performed in compliance with FDA-GLP, and they are considered to be the critical studies for assessment. Four groups of 10 males and 10 females (mice: B6C3F1; rats: SD and F344) individually housed were exposed to hydrogen chloride gas at concentrations of 0, 10, 20 and 50 ppm for 90 days (6 hours/day, 5 days/week). For male and female mice at 50 ppm, a decrease in body weight gain, food consumption and liver weight (male) was noted. For male SD rats at 50 ppm, a decrease in food consumption was observed. For F344 rats, a decrease in body weight gain was observed in males at 50 ppm and a decrease in food consumption was observed in both sexes at 20 and 50 ppm. No biologically significant difference was observed in urinalysis, haematology and serum chemistry. Inflammatory histopathological changes in lips or nasal cavity were observed in B6C3F1 mice and F344 rats above 10 ppm or in SD rats above 20 ppm. In addition, the histopathological examination of reproductive organs (testis, epididymis, prostate, seminal vesicle; ovary, uterus, oviduct, mammary glands) could not find any exposure related effects. The NOAEL for repeated dose inhalation toxicity, except for the local effects of irritation, is considered to be 20 ppm for rats and mice.

It is therefore considered appropriate to use the existing EU OEL for HCl as the starting point to quantify local DNELs for dichloromethyl(3, 3, 3-trifluoropropyl)silane.

Long-term exposure –Local effects:

 

Inhalation DNEL:

Since each mole of dichloromethyl(3, 3, 3-trifluoropropyl)silane (molecular weight 211.1 g/mol) produces two moles of HCl (molecular weight 36.46), it is appropriate to calculate the starting concentration of dichloromethyl(3, 3, 3-trifluoropropyl)silane that would result in an exposure concentration of 8 mg/m³ HCl, assuming complete hydrolysis.

The equivalent exposure level expressed as parent dichloromethyl(3, 3, 3-trifluoropropyl)silane is calculated as (MW (HCl) = 36.46 g/mol MW dichloromethyl(3, 3, 3-trifluoropropyl)silane = 211.1 g/mol):

Amount HCl produced by 1 mole dichloromethyl(3, 3, 3-trifluoropropyl)silane= 2 x 36.46 g/mol=68.92 g. Concentration of dichloromethyl(3, 3, 3-trifluoropropyl)silane required to produce 8 mg/m³ HCl= (211.1/ 68.92)*8= 24.50 mg/m³.

No additional assessment factors are applied to the OEL.

Inhalation DNEL (Long-term exposure - local effects, worker) : 24.50 mg/m³

Dermal DNEL: No suitable quantitative data are available.

Long term exposure – Systemic effects

Because of the corrosivity of the substance, the DNEL for local effects is considered sufficiently protective against potential systemic effects.

General Population - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

exposure based waiving

Acute/short term exposure

Hazard assessment conclusion:

exposure based waiving

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

exposure based waiving

Acute/short term exposure

Hazard assessment conclusion:

exposure based waiving

DNEL related information

General Population - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

exposure based waiving

Acute/short term exposure

Hazard assessment conclusion:

exposure based waiving

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

exposure based waiving

Acute/short term exposure

Hazard assessment conclusion:

exposure based waiving

General Population - Hazard via oral route

Systemic effects

Long term exposure

Hazard assessment conclusion:

exposure based waiving

Acute/short term exposure

Hazard assessment conclusion:

exposure based waiving

DNEL related information

Additional information - General Population

There is no potential for exposure of consumers via any route to dichloromethyl(3, 3, 3 -trifluoropropyl)silane, therefore DNELs for consumers are not calculated.