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Chemical Sampling Information (CSI)
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General Description

Synonyms: 3,3'Dimethylbenzidine

OSHA IMIS Code Number: 2450

Chemical Abstracts Service (CAS) Registry Number: 119-93-7

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: DD1225000; 14667

NIOSH Pocket Guide to Chemical Hazards, o-Tolidine: Chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): Appendix A3 (Confirmed Animal Carcinogen with Unknown Relevance to Humans)

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 0.02 mg/m3 Ceiling (60 min); Potential carcinogen


Health Factors

Carcinogenic Classification:
International Agency for Research on Cancer (IARC): Group 2B, possibly carcinogenic to humans (3,3'-Dimethylbenzidine and 3,3'-dimethylbenzidine-based dyes) [479 KB PDF, 63 pages]

National Toxicology Program (NTP): Reasonably anticipated to be a human carcinogen (3,3'- Dimethylbenzidine and Dyes Metabolized to 3,3'-Dimethlybenzidine) [183 KB PDF, 3 pages]
Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):
  • sampling media: Coated Glass Fiber Filters (37 mm) in 3 piece cassette. Coating is Sulfuric Acid.
    maximum volume: 100 Liters
    maximum flow rate:
    1.0 L/min
    current analytical method: Gas Chromatography; GC/ECD
    method reference: 2 (OSHA 71)
    sampling and analytical error: 0.13
    method classification: Fully Validated
    note: Within ten hours after sampling, transfer filter to glass vial containing 2 mL deionized water. Filters may be obtained by OSHA personnel from the Salt Lake Technical Center.

Conditions: Zorbax C18; 60% methanol 40% water; 1 mL/min; UV Det: 280; DL 0.01 ug/sample; C/P DB

Wipe Sampling Method:

  • sampling media: Glass Fiber Filter

Bulk Method:

  • Limit the amount of bulk submitted to one gram or one mL.
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