MOLYBDENUM, DUST & INSOLUBLE COMPOUNDS (as Mo) | OSHA.gov | Occupational Safety and Health Administration

MOLYBDENUM, DUST & INSOLUBLE COMPOUNDS (as Mo)†

Chemical Identification
CAS #	7439-98-7
Formula	Mo
Synonyms	molybdenum metal

Physical Properties
Physical description	Dark gray or black powder with a metallic luster.
Boiling point	8717°F	Molecular weight	95.9
Freezing point/melting point	4752°F	Vapor pressure	0 mmHg (approx)
Flash point		Vapor density
Specific gravity	10.28	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
Analyte code (IMIS no.)	1790
Sampling group	METALSSG-2
Sampler/Sampling media	Pre-assembled cassette with mixed cellulose ester filter (MCEF) 0.8 micron (25 or 37 mm) [MAWP025A0 or MAWP037A0]
Sampling time^*	240-480 min
Sampling volume (TWA)^*	480-960 L
Sampling flow rate (TWA)^*	2 L/min
Sampling volume (STEL/Peak/C)^*
Sampling flow rate (STEL/Peak/C)^*
Analytical method instruments	ICP
Method reference	OSHA ID-125G (fully validated)
Notes	Results are provided for the presence and amount or concentration of a specific element or elements. The stated identity of the actual sample contents (such as a specific form or compound) is based on the assumption that the material sampled is as identified by the compliance officer using available documentation of materials and processes. The physical form of a sample (dust, mist, or fume) is identified by the compliance officer using available documentation of materials and processes. Smaller filters recommended for sampling inside welding hoods.
Special requirements	For the entire suite of analytes listed in METALSSG-2, request analyte code 2587.

^* 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.

Bulk/Wipe Method
Wipe Sampler/Sampling media	Ghost Wipe [SKC 225-2414]
Bulk Method	Available

On-Site Screening Techniques
Device
Model/Type
Sampling information (see manufacturer instructions)

**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	15 mg/m³ (total dust)	REL-TWA		TLV-TWA	10 mg/m³ (inhalable particulate matter), 3 mg/m³ (respirable particulate matter) [1999]	PEL-TWA	10 mg/m³ (total dust), 3 mg/m³ (respirable)
PEL-STEL		REL-STEL		TLV-STEL		PEL-STEL
PEL-C		REL-C		TLV-C		PEL-C
Skin notation	N	Skin notation	NA	Skin notation	N	Skin notation	N
Notes: See 29 CFR 1910.1000 Table Z-1.		Notes: See Appendix D - Substances with No Established RELs.		Notes:		Notes:
Health factors: See NIH-NLM PubChem.		IDLH	5000 mg/m³
Carcinogenic classifications: Not listed		Notes:
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:

Additional Resources and Literature References

NOAA: CAMEO Chemicals - Molybdenum

NIOSH: Pocket Guide to Chemical Hazards - Molybdenum

Literature References

ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Carbon monoxide. See annual publication for most recent information.
Occupational Health Guidelines for Chemical Hazards. DHHS/ NIOSH Publication No. 81-123, (January 1981). Provides a table of contents of guidelines for many hazardous chemicals. The files provide technical chemical information, including chemical and physical properties, health effects, exposure limits, and recommendations for medical monitoring, personal protective equipment (PPE), and control procedures.
ATSDR: Toxicological profile for carbon monoxide. June 2012.
EPA: Integrated Science Assessment for Carbon Monoxide (Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-09/019F. January 29, 2010.
NIOSH: Criteria Document for a Recommended Standard - Occupational Exposure to Carbon Monoxide. 1972.
Sari I, Zengin S, Ozer O, Davutoglu V, Yildirim C, Aksoy M: Chronic carbon monoxide exposure increases electrocardiographic P-wave and QT dispersion. Inhal Toxicol. 20(9):879-84, July 2008.

Last Updated Date : 06/14/2023

Group Sampling Information
Sampling Media	Sampling Time (If there are exceptions they will be in Notes)	TWA Sampling Volume (If there are exceptions they will be in Notes)	TWA Flow Rate (If there are exceptions they will be in Notes)
mixed cellulose ester filter (MCEF)	240-480 min	480-960 L	2 L/min

Analytes Sampling Information
Analytes	IMIS Code	Wipe Sampling	Incompatibilities
Iron*	I200	Yes, with a Ghost Wipe
Vanadium*	V125	Yes, with a Ghost Wipe
Zinc*	Z100	Yes, with a Ghost Wipe
Chromium, Metal & Insoluble salts (as Cr)**	0685	Yes, with a Ghost Wipe	Hexavalent Chromium
Cobalt, Metal, Dust & Fume (as Co)	0720	Yes, with a Ghost Wipe	Tungsten
Copper Dust & Mists (as Cu)	0730	Yes, with a Ghost Wipe
Copper Fume (as Cu)	0731	Yes, with a Ghost Wipe
Iron Oxide Fume	1520	Yes, with a Ghost Wipe
Manganese, Compounds & Fume (as Mn)***	1620	Yes, with a Ghost Wipe
Molybdenum, Dust & Insoluble compounds, (as Mo)	1790	Yes, with a Ghost Wipe
Nickel, Metal, & Insoluble compounds (as Ni)	1840	Yes, with a Ghost Wipe
Vanadium, Respirable Dust & Fume	2571	Yes, with a Ghost Wipe
Zinc Oxide Fume	2610	Contact SLTC for information

Notes

Request any or all of these analytes together. Entire group can be requested with analyte code 2587.

Results for unrequested analytes in this group will be reported if significant amount are found.

There is no need to contact SLTC before sampling.

This analysis can be pre-analyzed gravimetrically if collected on a pre-weighted PVC filter obtained from SLTC.

*These 3 codes are used for bulk sample results in place of their metal oxides.

**Please note that this is NOT hexavalent chromium.

***For Manganese STEL take only a 10-30 L sample.

MOLYBDENUM, DUST & INSOLUBLE COMPOUNDS (as Mo)†

Chemical Identification

Physical Properties

Monitoring Methods Used by OSHA

Bulk/Wipe Method

On-Site Screening Techniques

Exposure Limits

Additional Resources and Literature References