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Chemical Sampling Information (CSI)
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General Description

Synonyms: Difluorodichloromethane; Fluorocarbon 12; Freon® 12; Genetron® 12; Halon® 122; Propellant 12; Refrigerant 12

Chemical Abstracts Service (CAS) Registry Number: 75-71-8

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: PA8200000

Department of Transportation Regulation Number (49 CFR 172.101) and Guide: 1028 126

NIOSH Pocket Guide to Chemical Hazards, Dichlorodifluoromethane: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

OSHA Permissible Exposure Limit (PEL):

General Industry: 29 CFR 1910.1000 Table Z-1 - 1000 ppm, 4950 mg/m3 TWA

Construction Industry: 29 CFR 1926.55 Appendix A - 1000 ppm, 4950 mg/m3 TWA

Maritime: 29 CFR 1915.1000 Table Z-Shipyards - 1000 ppm, 4950 mg/m3 TWA

American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 1000 ppm, 4950 mg/m3 TWA ; Appendix A4 - Not Classifiable as a Human Carcinogen

National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 1000 ppm, 4950 mg/m3 TWA

Health Factors

NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 15,000 ppm

Potential Symptoms: Dizziness, drowsiness, confusion; tremor, unconsciousness, asphyxia, cardiac arrhythmias, cardiac arrest; frostbite (from liquid)

Health Effects: Narcosis (HE8); Asphyxiant (HE17)

Affected Organs: Cardiovascular system, peripheral nervous system

Notes:

  1. Dichlorodifluoromethane, when at least 99.97% pure, is approved by the FDA as a direct-contact freezing agent for foods (21 CFR 173.355). It is now banned by the EPA, however, due to environmental concerns about stratospheric ozone depletion.
  2. Dichlorodifluoromethane has not been manufactured in the U.S. since 1995, although it was detected at least twice in at least one drinking water source in California during the period, 2002-2004.
  3. EPA's oral reference dose (daily oral exposure likely to be without an appreciable risk of deleterious effects during a lifetime) of dichlorodifluoromethane is 0.2 mg/kg/day.

Literature Basis:

Date Last Revised: 11/17/2005

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

  • sampling media: Two Charcoal Tubes in series (first tube 400/200 mg second 100/50 mg sections, both 20/40 mesh)
    analytical solvent: Methylene Chloride
    maximum volume: 4 Liters
    maximum flow rate: 0.05 L/min
    current analytical method: Gas Chromatography; GC/FID
    method reference: NIOSH Analytical Method (NIOSH 1018 [23 KB PDF, 4 pages])
    method classification: Fully Validated
    note: Refrigerate samples after collection and during shipment to the laboratory.

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