Comparison to Standards, Decision Making Flashcards
Out of all of the 600,000 chemicals used in the world, how many are formally regulated?
2000
What does OEL stand for?
Occupational Exposure Limit
What is the OSHA exposure limit?
PEL - permissible exposure limit
What is NIOSH’s exposure limit?
REL - recommended exposure limit
What is ACGIH exposure limit?
Threshold limit value
Describe the TLV
- many countries in Europe use
- best knowledge that we have to date
- may be the strictest
- published annually
Why is OSHA considered to be a performance standard?
-does not indicate how to maintain workplace below PEL, just regulates the limit
What type of standards described how to reach a certain endpoint?
Prescribed or design standards- not as common, usually up to you to determine how you will reach a certain limit
What is the healthy workforce theory?
More people that work are healthy, others who got sick left for one reason or another
Give an example of a prescribed or design standard
ventilation standards- tell you how ventilation system must be designed
What do OSHA’s comprehensive standards cover?
- PEL
- Medical Surveillance
- Prescribed control methods
What is OSHA’s general duty clause?
Employer is responsible for providing a workplace that is free of known hazards that can cause or are likely to cause serious injury or death
What is the equation for standard error?
SE = stddev / sqaure root (N)
N= sample size
What does T equal if N > 19?
2
What are the equations for the upper confidence limit and lower confidence limit?
UCL = mean + t(2-sided, alpha 0.05) (SE)
LCL = mean - T(2 sided, alpha = 0.05) (SE)
Give an example of a reason to take multiple measurements and use stats for measurements
One measurement may have been taken during abnormal air circulation (IE window open) which will cause it to be an outlier
Find SE, LCL, and UCL for:
n = 36
u = 20 ppm
std dev = 2.4
SE = 0.4
UCL = 20.8
LCL - 19.2
What documents provide the basis for occupational health and safety standards? Who puts them out?
NIOSH - criteria documents
Describe what the criteria documents usually contain
Review of scientific and technical knowledge on:
1) prevalence of hazards
2) existing health and safety risks
3) adequacy of control measures
Also show: how to measure, toxicology information, and RELS
True or False: Threshold limit values are the same as the threshold on a dose/response graph
False
Who created the TLV?
The American Conference of Governmental Industrial Hygienists- ACGIH
How often are the TLVs updated?
annually with notification of change
What do the TLVs indicate?
airborne concentrations of chemicals that cause no adverse effects to almost all workers
Is the TLV a regulatory standard?
no- professional standard
What is the time weighted average?
TWA- concentration of a chemical averaged over an 8-hour work day that workers can be exposed day after day over the course of a lifetime without adverse effect
What is the equation for TWA?
(T1C1+T2C2+TnCn) / 8
What is STEL?
Short term Exposure Limit- maximum concentration that an employee can be exposed to for 15 minutes
Many substances list TWA and STEL
What is the ceiling limit?
Concentration that should never be exceeded
What are some notations that TLVs contain?
Skin and cancer notations
What is the industrial hygiene process?
See slide
Hazard Assessment (Anticipate and Recognize)–> Exposure Risk assessment (evaluate) –> exposure management (Control)
Describe the hierarchy of OELs
Bottom to top (less data to more toxicological and epidemiological data)
1) Hazard Banding
2) Prescriptive OELs
3) Working OELs
4) Health based OELs (TLVs)
5) Quantitative based OELS (reguations- PEL and some NIOSH RELS)
Describe the quantitative based OELS
- best
- shown to decrease disease
- can be used for regulation
- some NIOSH RELs fit here, as well as OSHA PELs
Describe Health based OELS
- toxicology and epi data available
- protect most workers
- TLVs
Describe working or provisional OELs
- company or “in-house” limits
Describe perscriptive or process based OEL limits
aimed to reach no effect level
What is the least studied OEL used for chemicals?
hazard/ control banding
Describe hazard banding.
- Do not yet have a lot of data, but can compare to other chemicals.
- developed by pharma
- decision matrix with red, yellow, green based on hazards
Describe control banding
chart that looks at risk and exposure levels and shows corresponding controls. Use when you don’t have data, but want to do your best to control
What tools can you use to compare injury and illness rates to other similar organizations in your industry?
- Bureau of labor statistics (BLS)
- North American Industrial Classification COde
How do you calculate the incidence of injury / illness at your facility?
N/ EH * 200,000
N= # of injuries or illness
EH - number of hours worked by ALL employees in calendar year
200,000 - base for number of hours worked by 100 employees in a calendar year
What is worker compensation?
% of wages, medical, and death benefits paid by company for injury / death/ illness that prevents lawsuits (can only sue in case of negligence)
What are considerations with air sampling?
- what employees to sample
- how long sampling interval should be for measurement
- how many samples should be taken in a workday
- periods of exposure that should be sampled throughout the workday
- number of workdays per year for sampling and when?
- time to the result
What are considerations with sampling regarding the time to result?
- Do you need the measurement right away? Then do a direct reading in real time. Better for acute
- chronic/ do not need lab results right away? sampling media + 2 week lab time, more precise results
What employee or employees should be sampled?
- maximum risk group
- use exposure risk/ heath risk priority matrix
Who should you sample if you cannot determine the maximum risk group?
random sampling of a group of workers
What is the goal of selecting a random group to sample?
need a subgroup large enough that there is a high probability that the random sample will contain 1 worker with high exposure
What tool can be used to determine the sample size?
NIOSH Occupational Exposure Sampling Strategies Manual
How does the NIOSH Occupational Exposure Sampling Strategies Manual Work?
- 90% confidence interval, tells how many samples (or workers to test) from original group size (or number of employees).
- 90% confident that you will have at least 1 person with the highest 10% exposure
- also a 10% chance that you may miss someone with highest 10% of exposure
how many workdays during the year should be sampled and when?
Depends on OSHA regulations - substance specific. Some substances have specific intervals dependent on exposure level to the PEL
What is an example of a substance that has very specific details on the number of workdays during the year for samples and when?
Lead
Describe a normal distribution
function that shows the probability that a number will fall between two values, which could be - to + infiniti
bell curve
mean=median=mode
standard deviation
What are the differences between normal distribution and log normal distribution?
- lognormal can only be above 0, normal can have any value, even -
- lognormal- geometric mean, geometric deviation. Normal - arithmetic mean, arithmetic std deviation
- IH data best defined by log normal
What is log-normal distribution?
logarithms (base e or base 10) of data are normally distributed
Note: takes data with a skew and makes it normal
