Boron trifluoride

Toxicological Summary

Workers - Hazard via inhalation route

Systemic effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

1 mg/m³

DNEL related information

DNEL derivation method:

ECHA REACH Guidance

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

5 mg/m³

Most sensitive endpoint:

acute toxicity

DNEL related information

DNEL derivation method:

ECHA REACH Guidance

Overall assessment factor (AF):

12.5

Modified dose descriptor starting point:

NOAEC

Value:

62 mg/m³

Explanation for the modification of the dose descriptor starting point:

In the study retained (Rush 2008), the inhalation NOAEL was 24.6 mg/m3 of BF3 for acute respiratory tract irritation. Using Haber rule with n=3, the NOAEL for 15 minutes is 62 mg/m3

AF for dose response relationship:

1

Justification:

no specific concerns

AF for interspecies differences (allometric scaling):

1

Justification:

should not be applied

AF for other interspecies differences:

2.5

Justification:

as recommended by ECHA guidance

AF for intraspecies differences:

5

Justification:

as recommended by ECHA guidance

AF for the quality of the whole database:

1

Justification:

several studies available

AF for remaining uncertainties:

1

Local effects

Long term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

1 mg/m³

DNEL related information

DNEL derivation method:

ECHA REACH Guidance

Acute/short term exposure

Hazard assessment conclusion:

DNEL (Derived No Effect Level)

Value:

5 mg/m³

Most sensitive endpoint:

irritation (respiratory tract)

DNEL related information

DNEL derivation method:

ECHA REACH Guidance

Overall assessment factor (AF):

12.5

Dose descriptor starting point:

NOAEC

AF for dose response relationship:

1

Justification:

no concern

AF for interspecies differences (allometric scaling):

1

Justification:

should not be applied

AF for other interspecies differences:

2.5

Justification:

as recommended by ECHA guidance

AF for intraspecies differences:

5

Justification:

as recommended by ECHA guidance

AF for the quality of the whole database:

1

Justification:

several studies available

AF for remaining uncertainties:

1

Workers - Hazard via dermal route

Systemic effects

Long term exposure

Hazard assessment conclusion:

no hazard identified

Acute/short term exposure

Hazard assessment conclusion:

no hazard identified

DNEL related information

Local effects

Long term exposure

Hazard assessment conclusion:

medium hazard (no threshold derived)

Most sensitive endpoint:

skin irritation/corrosion

Acute/short term exposure

Hazard assessment conclusion:

medium hazard (no threshold derived)

Most sensitive endpoint:

skin irritation/corrosion

Workers - Hazard for the eyes

Local effects

Hazard assessment conclusion:

medium hazard (no threshold derived)

Additional information - workers

Long term, inhalation DNEL (workers)

The ECHA guidance authorizes a registrant to use a national OEL in place of deriving a DNEL in case where toxicological information and evaluations of health effects used for setting the national OEL are documented and available. Therefore, it is proposed to use the OEL proposed by Germany (1 mg/m3 for BF3, equivalent to 1.5 mg/m3 for BF3 dihydrate) (http://www.baua.de/cae/servlet/contentblob/664358/publicationFile/47955/900-bortrifluorid-dihydrat.pdf) in place of the derivation of the DNEL. This OEL value is the lowest occupational exposure level in Europe, and is based on available and relevant toxicological data at present.

The committee considered the subchronic study performed by Rush et al. (1986) as the study in which exposure was probably best reflecting occupational exposure conditions. In this study (Rush study, 1986), rats were exposed to aerosols of BF3 dihydrate for 13 weeks, the NOAEL was 6 mg/m3 and the LOAEL was 17 mg/m3 for effects on kidney (especially necrosis of the renal tubular epithelium in 2 rats at histology) . Clinical signs of respiratory irritation were seen at all dose levels, but without abnormal histological findings.

An overall assessment factor of 6 was established: 2 for time duration extrapolation, and 3 for intraspecies variability. This factor was reduced from 5 to 6 because BF3 and degradation products are excreted in urine following a non-enzymatic hydrolysis (therefore no polymorphism is taken into account). No interspecies factor was used since the exposition route of the experimental study was inhalation. Thus, applying these assessment factors and the preferred value approach, a health-based occupational exposure limit of 1 mg/m3 was recommended for boron trifluoride.

 

In conclusion, long-term inhalation DNEL for BF3 is1 mg/m3, equivalent to 0.35 ppm.

This DNEL is supposed cover both local effects (causing respiratory damages) and systemic effects observed in kidney (Rush studies).

 

Short term inhalation DNEL (workers)

 

Step 1: Selection of the relevant dose descriptor (starting point):

The 4 hours exposure inhalation study in rats (Rush, 2008) is selected for the DNEL derivation.

In that study, the inhalation NOAEL was 24.6 mg/m3 of BF3 for acute respiratory tract irritation. Using Haber rule with n=3, the NOAEL for 15 minutes is 62 mg/m3.

 

Step 2: Use of assessment factors: 12.5

Interspecies assessment, as recommended by ECHA : 2.5

Intraspecies, as recommended by ECHA : 5

Dose-response relationship: a factor of 1 is applied

Quality of database:1

 

In conclusion, short-term local inhalation DNEL for BF3 is 5 mg/m3, equivalent to 1.8 ppm

This DNEL is supposed cover both local effects (causing respiratory damages) and potential systemic effects.

General Population - Hazard via inhalation route

Systemic effects

Acute/short term exposure

DNEL related information

Local effects

Acute/short term exposure

DNEL related information

General Population - Hazard via dermal route

Systemic effects

Acute/short term exposure

DNEL related information

General Population - Hazard via oral route

Systemic effects

Acute/short term exposure

DNEL related information

Additional information - General Population

There are only industrial uses for BF3 and hence no direct exposure of the general population.

The releases of the substance in the environment (water, air, soil) are extremely low as its gaseous nature requires optimal containment. Furthermore, BF3 is instable in presence of water/humidity. Therefore, the general population is not exposed indirectly to BF3 via the environment.

Therefore no DNEL is calculated for the general population.