Occupational Tox

Question 1

Permissible Exposure Limits (PELs)

Answer 1

The only ones that are legally binding in US by OSHA

sets limit for legal unprotected worker exposure

considers technical and econominc feasibility

generally the least conservative limit

Question 2

Epidemiology Study Design Attributes

Answer 2

Question 3

Short Term Exposure Limit OEL

Answer 3

usually 15 minutes

concetration workers can be exposed to without irritation, irreversible tissue damage, toxic effects, or significant narcosis

occur no more than 4 times a day with at least 60 minutes between exposures

useful for fast acting compounds

Question 4

Recommended Exposure Limit (RELs)

Answer 4

NIOSH

ususually more conservative than PELs and based on a 10 hour workday

no requirement to consider feasibility

Question 5

Time Weighted Average OEL

Answer 5

TWA

usually an 8 hour workday

concentration over a full work week to which nearly all workers may be repeatedly exposed, day after day

Question 6

Ceiling limit OEL

Answer 6

should never be exceeded during any part of the working exposure (i.e. physical irritation)

Question 7

Threshold Limit Values (TLVs)

Answer 7

ACGIH (Industrial hygienists)

usually more conservative than PELs, often more conservative than RELs

No requirement to consider feasibility

8 hour day

derived by volunteer committees in the field

usually the most conservative