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Mercury Standards
Occupational Safety and Health Standards
The Occupational Safety and Health Administration (OSHA) regulation Title 29 of the Code of Federal
Regulations (CFR) 1910.1000, Air Contaminants, Table Z-2, and an OSHA Compliance Directive Interpretation
of 9 September 1996 regarding mercury exposure limits has set the Permissible Exposure (PEL) for all forms
of mercury at 0.10 milligrams per cubic meter (mg/m3) of air (equivalent to 6.1 parts per billion, ppb). The
Permissible Exposure Limit (PEL) is an eight-hour Time Weighted Average (TWA) concentration limit in air that
nearly all workers can be exposed to without adverse health effects. The American Conference of
Governmental Industrial Hygienists (ACGIH) Threshold Limit Values for Chemical Substances and Physical
Agents for 2001 has set recommended air standards for the elemental and inorganic forms of mercury
(including inorganic mercury vapor) at 0.025 milligrams per cubic meter (mg/m3) as an eight-hour Threshold
Limit Value (TLV) Time Weighted Average (TWA) concentration in air. A “Skin” notation is also designated with
the standard indicating skin, eye and mucous membrane contact as a significant pathway of absorption.
Table 2 provides a summary of mercury vapor exposure limits by various organizations including OSHA,
ACGIH, the National Institute of Occupational Safety and Health (NIOSH) and the National Academy of
Sciences (NAS).
Table 2. Mercury Vapor Exposure Limits Summary
OSHA PEL
8-Hour
TWA
(mg/m
3
)
ACGIH
TLV
8-Hour
TWA
(mg/m
3
)
ACGIH 30-
minute
Excursion
Limit
(mg/m
3
)
ACGIH
Instantaneous
Excursion Limit
(mg/m
3
)
NAS
SMAC
1-Hour
TWA
(mg/m
3
)
NAS SMAC
24-Hour
TWA
(mg/m
3
)
Table Abbreviations and Notes
American Conference of Governmental Industrial Hygienists - 2002 Threshold Limit Values
Immediately Dangerous To Life And Health
Milligrams Per Cubic Meter (air)
National Academy of Sciences
National Institute of Occupational Safety and Health
Permissible Exposure Limit
Parts per billion (in air)
Occupational Safety and Health Administration
Recommended Environmental Exposure Limit
Percutaneous (dermal) exposure (as route of exposure)
Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants (1996)
Note: When maintained and operated properly, emissions from the Bulb Eater
®
3 should be well under all
applicable mercury exposure requirements. Test results available upon request.