CHMM Test Study Guide
Threshold limit value short-term exposure limit (TLV-STEL) - CORRECT ANSWER-
maximum concentration averaged over 15 minute period, to which healthy adults can be
safely exposed for up to 15 minutes continuously (4 x a day with at least 60 minutes
between each exposure)
Threshold limit value ceiling (TLV-C) - CORRECT ANSWER-maximum concentration
averaged to which healthy adults can be exposed without risk of injury. Should not be
exceeded during any part of the working exposure
Can a TLV become PEL - CORRECT ANSWER-Yes
Immediately dangerous to life and health value (IDLH) - CORRECT ANSWER-
maximum level to which a healthy worker can be exposed for 30 minutes and escape
without suffering irreversible health effects or impairmen. For oxygen depleting
atmosphere, less than or equal to 19.5% and for oxygen enriched atmosphere, greater
than or equal to 23.5%
Heat Stress - CORRECT ANSWER-TLV for heat stress for both INDOOR and
OUTDOOR work are: based on the wet bulb globe temperature (WBGT Index). Note:
Dry bulb globe temperature (DBGT) is used when there is no radiation effect
Independent Effect - CORRECT ANSWER-2 + 2 + 2; substances exert their own toxicity
independent of each other. Ex: exposure to lead vs. sulfuric acid
Additive Effect - CORRECT ANSWER-1 + 1 = 2; The total effect is sum of the two
individual effects
Ex: Toluene + Xylene . Additive Exposure (exposure to a mixture targeting the same
organ):
Synergism - CORRECT ANSWER-1 +1 = 5 (30 to 80 x greater risk- combined effect >
sum effect of each agent). Ex: CCl4 + EtOH = increased liver injury and Asbestos +
Smoking = increased lung cancer
Potentiation - CORRECT ANSWER-1 + 0 = 3; not a toxin (for a particular target organ)
that in combination with a toxin, enhances the toxins effect
Antagonism - CORRECT ANSWER-1 + 1 < 2; One chemical opposes the effect of
another. Ex: EDTA + lead, chelating agents. Leads to develop the Antidotal therapy
How to evaluate employee exposure to airborne hazards - CORRECT ANSWER-
Personal air monitoring is conducted to evaluate employee exposure to airborne
,hazards before conducting air monitoring, it is necessary to plan the sampling by first
understand the potential hazards and then deciding what compounds are chemicals will
be tested period the potential toxic exposures must be cross reference with the list of
Permissible Exposure Limits and a Threshold Limit Values, if there is no establish
exposure limit, it is difficult to act on the results of an analysis. However, in the case of
organic chemicals, there may be established exposure limits for total hydrocarbons that
can be used.
Darcy's Law - CORRECT ANSWER-J=Ki is Darcy's Law, where J = Water flux in m/s, K
= hydraulic conductivity in m/s, i = hydraulic gradient (unitless). This law helps to
calculate the velocity and travel time of pollutants in ground water.
Q = KA (H1-H2)/L - CORRECT ANSWER-Q= discharge in gallons or cubic feet /unit of
time
K = Hydraulic Conductivity (measure of aquafier's ability to transmit water) expressed in
cm/sec or ft/day
A = cross sectional area (the area of water moves through horizontally)
(H1-H2)/L = head pressure lost term, dimensional quantity
L= Linear distance between H1 and H2 locations.
Sand - CORRECT ANSWER-Soil: has high porosity because it is not compacted.
Velocity of ground water in clay - CORRECT ANSWER-Ground water velocity is the
lowest in clay
Porosity - CORRECT ANSWER-Clay (Porosity = 50) > Soil (porosity = 55) > Sand
(Porosity = 25) > Gravel (Porosity = 20). Therefore, Sand would be the most effective in
purifying polluted groundwater.
7- Common OSHA Chemical Hazards: - CORRECT ANSWER-Flammables, Corrosives,
Oxidizers, Reactives, Explosives, Toxics, and Radioactive
(i) Flammables - CORRECT ANSWER-Flammable: Flash point is the temperature at
which a liquid gives off enough vapor to be ignited in air by a spark or other ignition
source. In general liquids/solids do not burn, their vapors do. Highly flammable, pose a
risk of liberation of a toxic gas, or pose an explosion hazard.
Fire Tetrahedron: fuel, heat, oxygen, and free radicals
- F.P. ≤ 140ºF (EPA calls it ignitable)
-F.P. ≤ 141ºF (DOT calls it flammable)
-F.P. between 100 and 200 ºF (DOT calls it combustible)
-F.P. ≤ 100 ºF (OSHA calls it flammable)
-Fire Triangle: Fuel, heat and oxygen
-Fire Tetrahedron: O2, heat, fuel, free radicals
, -Flammability Limits (Upper Flammability Limit): higher end of range of fuel/air vapor
mixture when it will burn upon ignition.
-Flammability Limits (Lower Flammability Limits): lower end of range of fuel/air vapor
mixture when it will burn upon ignition.
-Autoignition Temperature: Some materials will ignite spontaneously at a given
temperature without any source of ignition.
-Analytical Test for flammability: "closed cup"
Using the concept of Lower Flammability Limits (LEF) & Upper Flammability Limit
(UFL), when will a vapor will burn - CORRECT ANSWER-above its LEF and below UFL,
a vapor will burn
What is the easiest way to avoid fire and explosion when working with flammables? -
CORRECT ANSWER-Control Ignition Sources
(ii) Corrosives - CORRECT ANSWER--DOT definition: Liquid/solid that will cause visible
tissue destruction or severe corrosion on steel/Aluminium
-GHS definition: 6.25 mm (0.25 in) per year or irreversible damage to skin
(iii) Oxidizers - CORRECT ANSWER-presence of oxygen needed to cause burning,
rapid exothermic reaction. Oxidizer + Organics = Explosion
Perchloric Acid - CORRECT ANSWER-A very strong oxidizer, which can cause fire and
explosion hazard. If evaporation is conducted under a hood equipped with a water-fall,
the fire & explosion hazard can be negated
(iv) Reactives - CORRECT ANSWER--Pyrophorics are spontaneous ignitable when
exposed to air at T≤130 oF, per DOT they catch fire in ≤ 5 min
o White Phosphorous
o Trialkyl aluminium compounds
o Titanium dichloride
- Water Reactives: Alkali metals; metal hydrides, amides, and halides; organic and
inorganic acid halides, phosphorous pentoxide, calcium carbide, and anhydrides of low
molecular weight. Rxn w/ H2O causes release of flammable/toxic gas/HCN gas.
(v) Explosives - CORRECT ANSWER--They release large amount of energy
spontaneously or via friction, impact, heat, light or combination
-Rapid oxidation
-Gun powder, black powder, pyrotechnics
-Sodium Azide (airbags)
-Picric Acid
-Organic Peroxides (polymerization catalysts)
-Nitroglycerine (dynamite)
(vi) Toxic - CORRECT ANSWER-A) Acute Toxic Agents: cause minor effect such as
skin/eye irritation or lethal. They are irritants and asphyxiants
Threshold limit value short-term exposure limit (TLV-STEL) - CORRECT ANSWER-
maximum concentration averaged over 15 minute period, to which healthy adults can be
safely exposed for up to 15 minutes continuously (4 x a day with at least 60 minutes
between each exposure)
Threshold limit value ceiling (TLV-C) - CORRECT ANSWER-maximum concentration
averaged to which healthy adults can be exposed without risk of injury. Should not be
exceeded during any part of the working exposure
Can a TLV become PEL - CORRECT ANSWER-Yes
Immediately dangerous to life and health value (IDLH) - CORRECT ANSWER-
maximum level to which a healthy worker can be exposed for 30 minutes and escape
without suffering irreversible health effects or impairmen. For oxygen depleting
atmosphere, less than or equal to 19.5% and for oxygen enriched atmosphere, greater
than or equal to 23.5%
Heat Stress - CORRECT ANSWER-TLV for heat stress for both INDOOR and
OUTDOOR work are: based on the wet bulb globe temperature (WBGT Index). Note:
Dry bulb globe temperature (DBGT) is used when there is no radiation effect
Independent Effect - CORRECT ANSWER-2 + 2 + 2; substances exert their own toxicity
independent of each other. Ex: exposure to lead vs. sulfuric acid
Additive Effect - CORRECT ANSWER-1 + 1 = 2; The total effect is sum of the two
individual effects
Ex: Toluene + Xylene . Additive Exposure (exposure to a mixture targeting the same
organ):
Synergism - CORRECT ANSWER-1 +1 = 5 (30 to 80 x greater risk- combined effect >
sum effect of each agent). Ex: CCl4 + EtOH = increased liver injury and Asbestos +
Smoking = increased lung cancer
Potentiation - CORRECT ANSWER-1 + 0 = 3; not a toxin (for a particular target organ)
that in combination with a toxin, enhances the toxins effect
Antagonism - CORRECT ANSWER-1 + 1 < 2; One chemical opposes the effect of
another. Ex: EDTA + lead, chelating agents. Leads to develop the Antidotal therapy
How to evaluate employee exposure to airborne hazards - CORRECT ANSWER-
Personal air monitoring is conducted to evaluate employee exposure to airborne
,hazards before conducting air monitoring, it is necessary to plan the sampling by first
understand the potential hazards and then deciding what compounds are chemicals will
be tested period the potential toxic exposures must be cross reference with the list of
Permissible Exposure Limits and a Threshold Limit Values, if there is no establish
exposure limit, it is difficult to act on the results of an analysis. However, in the case of
organic chemicals, there may be established exposure limits for total hydrocarbons that
can be used.
Darcy's Law - CORRECT ANSWER-J=Ki is Darcy's Law, where J = Water flux in m/s, K
= hydraulic conductivity in m/s, i = hydraulic gradient (unitless). This law helps to
calculate the velocity and travel time of pollutants in ground water.
Q = KA (H1-H2)/L - CORRECT ANSWER-Q= discharge in gallons or cubic feet /unit of
time
K = Hydraulic Conductivity (measure of aquafier's ability to transmit water) expressed in
cm/sec or ft/day
A = cross sectional area (the area of water moves through horizontally)
(H1-H2)/L = head pressure lost term, dimensional quantity
L= Linear distance between H1 and H2 locations.
Sand - CORRECT ANSWER-Soil: has high porosity because it is not compacted.
Velocity of ground water in clay - CORRECT ANSWER-Ground water velocity is the
lowest in clay
Porosity - CORRECT ANSWER-Clay (Porosity = 50) > Soil (porosity = 55) > Sand
(Porosity = 25) > Gravel (Porosity = 20). Therefore, Sand would be the most effective in
purifying polluted groundwater.
7- Common OSHA Chemical Hazards: - CORRECT ANSWER-Flammables, Corrosives,
Oxidizers, Reactives, Explosives, Toxics, and Radioactive
(i) Flammables - CORRECT ANSWER-Flammable: Flash point is the temperature at
which a liquid gives off enough vapor to be ignited in air by a spark or other ignition
source. In general liquids/solids do not burn, their vapors do. Highly flammable, pose a
risk of liberation of a toxic gas, or pose an explosion hazard.
Fire Tetrahedron: fuel, heat, oxygen, and free radicals
- F.P. ≤ 140ºF (EPA calls it ignitable)
-F.P. ≤ 141ºF (DOT calls it flammable)
-F.P. between 100 and 200 ºF (DOT calls it combustible)
-F.P. ≤ 100 ºF (OSHA calls it flammable)
-Fire Triangle: Fuel, heat and oxygen
-Fire Tetrahedron: O2, heat, fuel, free radicals
, -Flammability Limits (Upper Flammability Limit): higher end of range of fuel/air vapor
mixture when it will burn upon ignition.
-Flammability Limits (Lower Flammability Limits): lower end of range of fuel/air vapor
mixture when it will burn upon ignition.
-Autoignition Temperature: Some materials will ignite spontaneously at a given
temperature without any source of ignition.
-Analytical Test for flammability: "closed cup"
Using the concept of Lower Flammability Limits (LEF) & Upper Flammability Limit
(UFL), when will a vapor will burn - CORRECT ANSWER-above its LEF and below UFL,
a vapor will burn
What is the easiest way to avoid fire and explosion when working with flammables? -
CORRECT ANSWER-Control Ignition Sources
(ii) Corrosives - CORRECT ANSWER--DOT definition: Liquid/solid that will cause visible
tissue destruction or severe corrosion on steel/Aluminium
-GHS definition: 6.25 mm (0.25 in) per year or irreversible damage to skin
(iii) Oxidizers - CORRECT ANSWER-presence of oxygen needed to cause burning,
rapid exothermic reaction. Oxidizer + Organics = Explosion
Perchloric Acid - CORRECT ANSWER-A very strong oxidizer, which can cause fire and
explosion hazard. If evaporation is conducted under a hood equipped with a water-fall,
the fire & explosion hazard can be negated
(iv) Reactives - CORRECT ANSWER--Pyrophorics are spontaneous ignitable when
exposed to air at T≤130 oF, per DOT they catch fire in ≤ 5 min
o White Phosphorous
o Trialkyl aluminium compounds
o Titanium dichloride
- Water Reactives: Alkali metals; metal hydrides, amides, and halides; organic and
inorganic acid halides, phosphorous pentoxide, calcium carbide, and anhydrides of low
molecular weight. Rxn w/ H2O causes release of flammable/toxic gas/HCN gas.
(v) Explosives - CORRECT ANSWER--They release large amount of energy
spontaneously or via friction, impact, heat, light or combination
-Rapid oxidation
-Gun powder, black powder, pyrotechnics
-Sodium Azide (airbags)
-Picric Acid
-Organic Peroxides (polymerization catalysts)
-Nitroglycerine (dynamite)
(vi) Toxic - CORRECT ANSWER-A) Acute Toxic Agents: cause minor effect such as
skin/eye irritation or lethal. They are irritants and asphyxiants
