SILICA, AMORPHOUS INCLUDING NATURAL DIATOMACEOUS EARTH†

Chemical Identification
Chemical Identification
CAS # Varies
Formula

SiO₂

Synonyms

diatomaceous earth; diatomaceous silica; diatomite; precipitated amorphous silica; silica gel; silicon dioxide (amorphous); vitreous silica

Physical Properties
Physical Properties
Physical description Transparent to gray, odorless powder.
Boiling point 4046°F Molecular weight 60.1
Freezing point/melting point 3110°F Vapor pressure 0 mmHg (approx)
Flash point Vapor density
Specific gravity 2.20 Ionization potential
Lower explosive limit (LEL) Upper explosive limit (UEL)
NFPA health rating NFPA fire rating
NFPA reactivity rating NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs
Monitoring Methods Used by OSHA
Monitoring Methods Used by OSHA
Analyte code (IMIS no.) S122 (total); request using analyte code 9135
Sampling group
Sampler/Sampling media Tared low-ash 37 mm PVC filter, 5 microns [SLTC108]
Sampling time*

240-480 min

Sampling volume (TWA)*

960 L

Sampling flow rate (TWA)*

2 L/min

Sampling volume (STEL/Peak/C)*
Sampling flow rate (STEL/Peak/C)*
Analytical method instruments Gravimetric
Method reference OSHA PV2121 (partially validated)
Notes

If the net weight of the sample yields a concentration below the PEL after considering the associated SAE , the SLTC will perform no further work on the sample and the sample air concentration will be reported as the calculated gravimetric air concentration. If the net weight corresponds to an amount greater than the PEL value after considering the associated SAE, the sample may be analyzed for  the applicable component and appropriate results will be reported.

Special requirements

FOR TOTAL DUST SAMPLES, DO NOT USE A CYCLONE!!

* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.

Wipe Method
Wipe Method
Sampler/Sampling media
Bulk Method
Bulk Method
On-Site Screening Techniques
On-Site Screening Techniques
Device
Model/Type
Sampling information
(see manufacturer instructions)
Exposure Limits
Exposure Limits
OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
NIOSH REL
Up to 10-hour TWA
(ST) STEL
(C) Ceiling
ACGIH TLV©
8-hour TWA
(ST) STEL
(C) Ceiling
CAL/OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
PEL-TWA

20 mppcf or (80 mg/m³)/(%SiO2)

REL-TWA

6 mg/m³

TLV-TWA PEL-TWA

6 mg/m³ (total dust), 3 mg/m³ (respirable dust), 6 mg/m³ (precipitated and gel)

PEL-STEL REL-STEL TLV-STEL PEL-STEL
PEL-C REL-C TLV-C PEL-C
Skin notation

N

Skin notation

N

Skin notation

NA

Skin notation

N

Notes:

See 29 CFR 1910.1000 Table Z-3, Mineral Dusts.

Notes: Notes:

Not established

Notes:

See footnote (n).

Health factors:  See NIH-NLM PubChem. IDLH

3000 mg/m³

Carcinogenic classifications: IARC-3 Notes:
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
Additional Resources and Literature References
Additional Resources and Literature References

NOAA: CAMEO Chemicals - Silica, amorphous

NIOSH: Pocket Guide to Chemical Hazards - Silica, amorphous

Literature References

Last Updated Date : 01/11/2021