Chemicals and Their Hazards

1. Chemicals and Their Hazards
Mrs.R.P.Nimbalkar
Assistant Professor,
Chemical Engineering,
PIET,Nagpur

2. Three categories of threshold limit
values
• Threshold Limit Value – Time-Weighted Average (TLV-TWA): The concentration of a hazardous substance
in the air averaged over an 8-hour workday and a 40-hour workweek to which it is believed that workers
may be repeatedly exposed, day after day, for a working lifetime without adverse effects.
• Threshold Limit Value – Short-term exposure (TLV-STEL): A 15-minute time weighted average exposure
that should not be exceeded at any time during a workday, even if the overall 8-hour TLV-TWA is below the
TLV-TWA. Workers should not be exposed more than four times per day to concentrations between TLV-
TWA and TLV-STEL. There should be at least a 60 minute interval between exposures. The short-term
exposure threshold has been adopted to account for the acute effects of substances that have primarily
chronic affects.
• Threshold Limit Value – Ceiling (TLV-C): This is the concentration that should not be exceeded during any
part of the working exposure. Peak exposures should be always controlled. For substances that do not
have TLV-TWA or TLV-C established, the maximum admissible peak concentrations must not exceed:
• Three-times the value of the TLV-TWA for no more than 15 minutes, no more than four times per workday.
Exposures must be at least 1 hour apart during the workday.
• Five times the TLV-TWA under any circumstances.
• The units of measures for the threshold limit values are ppm and mg/m3. The TLVs for aerosols are
expressed usually in mg/m3. The TLVs for gases and vapours are expressed in ppm or mg/m3.

3. Name of
Chemical
Properties Causes Prevention/ protection
Acetonitrile/
ethyl
nitril/methyl
cyanide
B.P. 81
°C ,flash
point
2°C,auto
Ignition temp
525°C,densit
y 800 kg/m3 ,
density (w.r.to
air) 1.4 kg/m3
Explosive limit
3 – 16%v in air.
TLV-TWA
value is
40ppm(67
mg/m3)
Flammable, toxic,
forms explosive air
vapour mixture,If
inhaled or ingested
severe breathing
problem,headache,
dizziness,cramp,and
weakness feeling
If acetonitrile tank catches
fire,keep it cool by water
spray,dry powder,alcohol
resistant foam, carbondioxide.
For handling
acetonitrile,respiratory
protection,gloves,protective
clothing,face shield.
Adequete ventilation is
necessary.
If operator inhales
acetonitrile ,transfeer him to
fresh air,call doctor,remove
contaiminated clothing,water
shower.
Keep acetonitril in
cool,dry,fire proof place and
should not allow to come in
contact with oxidants.

4. Name of
Chemical
Properties Causes Prevention/ protection
Acetyl
Chloride/
ethanoyl
chloride
B.P. 52
°C ,flash point
4°C,auto
Ignition temp
390°C,density
1100 kg/m3 ,
density (w.r.to
air) 2.7 kg/m3
It dissolves and
reacts with air.
Above 5% by
volume in air, it
forms explosive
mixture.
It is highly flammable,
corrosive and can
cause fire and
explosion with some
reaction. Explosive
mixture with air.
If spillage occurs,
collect it in sealed
container. Soak the
place with dry sand or
inert adsorbent.(in
presence of expert.)
Acetyl Chloride fire can be
controlled by dry powder and
carbon dioxide. Water and water
based fire extinguishers are never
allowed. For handling or
processing of acetyl chloride
adequate ventilation, respiratory
protection, gloves, protective
clothing, face & eye shield is
necessary.
If operator inhales acetyl chloride ,
transfer him to fresh air, call
doctor,
Store it in cool, dry fire proof
place away from bases and
alcohols.

5. Name of
Chemical
Properties Causes Prevention/ protection
Butyl
Amine/1-
aminobutan
e
Colorless liquid
with
characteristic
odour. B.P. 78
°C ,flash point -
12°C,auto
Ignition temp
310°C,density
700 kg/m3 ,
density (w.r.to air)
2.5 kg/m3
Explosive limit in
air by volume %
is 1.7 -10.0.TLV-
TWA is 5 ppm
It is extremely
flammable, irritant
and forms an
explosive air-
vapour mixture.
Explosive mixture
with air.
If spillage occurs,
collect it in sealed
container. Soak the
place with dry
sand or inert
adsorbent.(in
presence of
expert).
Butyl Amine fire can be controlled
by dry powder ,alcohol resistant
foam, large quantity of water and
carbon dioxide.
For handling or processing of butyl
amine adequate ventilation,
respiratory protection, gloves,
protective clothing, face & eye
shield is necessary.
If operator inhaled or ingested ,it
causes sore throat,
cough ,shortness of breath, severe
breathing problem, abdominal
pain,diarrhea,vomitting etc. To eyes
it causes redness ,pain and
impaired vision. Inhalation of butyl
amine develops lung edema several
hours later and is aggravated by
physical exertion.
Store it in fire proof place away
from oxidants, open flame, spark
and strong oxidants.

6. Name of
Chemical
Properties Causes Prevention/ protection
Acryl
Amide/Vinyl
amide
It is available in
white crystals or
white powder.
M.P. 84 °C,
density 1100
kg/m3 ,
It is soluble in
water.(215
gm/100 ml of
water at 30°C.)
Its TLV is 0.03
mg/m3
It is toxic ,
combustible and
its finely dispersed
particles forms an
explosive mixture
on contact with air.
If spillage occurs,
collect it in sealed
container in full
protection.(in
presence of
expert.)
Acryl amide fire can be controlled
by dry powder and water spray.
If operator inhaled or ingested ,it
causes sore throat,
cough ,tiredness ,feeling of
weakness , abdominal pain
slackness of muscles etc.
For handling or processing of acryl
amide adequate ventilation,
respiratory protection, gloves,
protective clothing, face & eye
shield is necessary.
If operator inhales acryl amide,
transfer him to fresh air , remove
contaminated clothing , offer first
aid and call doctor.
Store it in cool , dark place away
from open flames.
Regular medical check up of
personnel working in the plant is

7. Name of
Chemical
Properties Causes Prevention/ protection
Acrylonitrile
/ Vinyl
Cyanide or
Cyanoethyle
ne
Colorless liquid
with
characteristic
odour. B.P. 77
°C , flash point -
5°C , auto
Ignition temp
480°C , density
800 kg/m3 ,
density (w.r.to air)
1.83 kg/m3.
Explosive limit in
air is 2.8-28% by
volume.
Its TLV is 2ppm
(1.83 mg/m3)
It is flammable,
toxic , forms an
explosive air
vapour mixture.
If spillage occurs,
collect it is
soaked up with
sand or inert
adsorbent and
transferred to
safe place.(in
presence of
expert.)
Acrylonitrile fire can be controlled by
dry powder ,foam and carbon
dioxide.
If operator inhaled or ingested ,it
causes sore throat, severe breathing
difficulties , dizziness nausea , feeling
of weakness , abdominal pain
slackness of muscles etc. It causes
redness and pain to eyes.
For handling or processing of acrylo
nitrile adequate ventilation,
respiratory protection, gloves,
protective clothing, face & eye
shield is necessary.
If operator inhales acryl amide,
transfer him to fresh air , remove
contaminated clothing and call
doctor.
Store it in cool , dark ,fire proof place
away from oxidants ,strong bases
and from open flames.

8. Name of
Chemical
Properties Causes Prevention/ protection
Allyl Alcohol
/ Vinyl
carbinol or 2
–propenyl
alcohol
Colorless liquid
with pungent
odour. B.P. 97
°C , flash point
21°C , auto
Ignition temp
375°C , density
900 kg/m3 ,
density (w.r.to air)
(5.8kg/m3) .
Explosive limit in
air is 2.5-18% by
volume.
Its TLV is 2ppm
(1.83 mg/m3)
It is flammable,
toxic , above
21°C forms
explosive vapour-
air mixture.
If spillage occurs,
collect it is
soaked up with
sand or inert
adsorbent and
transferred to
safe place.(in
presence of
expert.)
Acrylonitrile fire can be controlled by
dry powder ,alcohol resistant foam ,
large quantity of water and carbon
dioxide.
If operator inhaled or ingested ,it
causes sore throat, cough, severe
breathing difficulties ,headache ,
nausea , feeling of weakness ,
abdominal pain etc. It causes
redness , pain and impaired vision
and light sensitivity to eyes.
For handling or processing of allyl
alcohol adequate ventilation,
respiratory protection, gloves,
protective clothing, face & eye
shield is necessary.
If operator inhales allyl alcohol,
transfer him to fresh air , offered first
aid and call doctor.
Store it in cool , dark ,fire proof place
away from oxidants and from open
flames.

9. Name of
Chemical
Properties Causes Prevention/ protection
Ammonium
Bichromate
Available in
yellow or orange
red Density 2150
kg/m3 , soluble
in water
(36gm/100 ml).
Explosive limit in
air is 2.5-18% by
volume.
Its TLV is 0.05
mg/m3.
Heating
ammonium
bichromate in a
confined space
can cause
explosion . Many
chemical
reactions with
ammonium
bichromate
Ammonium Bichromate fire can be
controlled by dry powder or water.
If inhaled or ingested ,it causes sore
throat, cough, severe breathing
difficulties ,headache , nausea ,
vomitting, abdominal pain etc.
For handling or processing of
ammonium bichromate adequate
ventilation, respiratory protection,
gloves, protective clothing, face &
eye shield is necessary.
If operator inhales ammonium
bichromate , transfer him to fresh
air , keep him in half sitting position
and offer necessary medical facility.
Store it in fire proof place away from
combustible substances , reducing
agents and strong bases ,open
flames , sparks.
Eating , drinking and smoking is
strictly prohibited in area.

10. Name of
Chemical
Properties Causes Prevention/ protection
Benzene
also called
as coal
naphtha,be
nzol,carbon
oil
Colorless liquid
with
characteristic
odour.Flash point
-11°C,B.P.
80°C,auto-
ignition
temperature
555°C. Density
900 kg/m3 , its
vapour heaviour
than air (2.7
kg/m3).
Explosive limit in
air is 1.2-8% by
volume.
Its TLV is 10 ppm
(32mg/m3).
It is extremely
flammable , toxic
and forms
explosive air
vapour mixture .
Flow , agitation
can induce and
build up
electrostatic
charge since it
has low thermal
conductivity.
Benzene fires can be controlled by
dry powder ,foam and carbon
dioxide.
If inhaled or ingested ,it causes sore
throat, cough, severe breathing
difficulties ,headache , nausea ,
vomiting, abdominal pain etc.
In handling and processing of
benzene adequate ventilation,
respiratory protection, gloves,
protective clothing, face & eyes
shield are necessary.
An infected person should be
transferred to fresh air , provide
artificial respiration and offer
necessary medical facility.
Storage in fire proof area away from
oxidants ,open flames , sparks etc.
Eating , drinking and smoking is
strictly prohibited in area.

11. 11
Electrostatic Charge and Thermal Conductivity
• Electrostatic charges. Static electricity or an electrostatic charge is a deficiency or
excess of electrons which occurs on ungrounded or insulating surfaces. It is
produced by triboelectric charges, charges that are generated by friction between
two surfaces, such as the movement of paper through a copier or printer. Charges
once accumulated are difficult to dissipate. The dissipation of an electrostatic-
charge occurs through shocks and sparks which can be hazardous in a flammable
atmosphere. Therefore, the presence of a static charge in textiles can be a major
hazard in explosives, paper, printing, electronics, plastics, and the photographic
industry (Bajaj et al., 1992))
• The thermal conductivity of a material is a measure of its ability to conduct heat.
It is commonly denoted byΚ,κ,λ .
• Heat transfer occurs at a lower rate in materials of low thermal conductivity than
in materials of high thermal conductivity. For instance, metals typically have high
thermal conductivity and are very efficient at conducting heat, while the opposite
is true for insulating materials like Styrofoam. Correspondingly, materials of high
thermal conductivity are widely used in heat sink applications, and materials of
low thermal conductivity are used as thermal insulation. The reciprocal of thermal
conductivity is called thermal resistivity.

12. Name of
Chemical
Properties Causes Prevention/ protection
Bromine Fuming Reddish
brown liquid
with pungent
odor . B.P.
59°C,auto-
ignition
temperature
555°C. Density
900 kg/m3 , its
vapour heaviour
than air (2.7
kg/m3).
Its TLV –TWA
value is 0.1 ppm
(0.66
mg/m3) .(Lungs
adema) STEL is
0.3 ppm (2
mg/m3)
It is non-
combustible ,
extremely
corrosive and
reacts violently
with many
organic
compounds ,
many metals and
phosphorous.
Heating with
hydrogen can
cause risk of fire
and explosion
both.
Benzene fires can be controlled any type
of fire extinguisher.
If inhaled or ingested ,it causes sore throat,
cough, severe breathing
difficulties ,headache , nausea , vomiting,
abdominal pain etc.
In handling and processing of bromine
adequate ventilation, respiratory
protection, gloves, protective clothing,
face & eyes shield are necessary.
An infected person should be transferred
to fresh air ,remove contaminated cloths ,
wash with adequate water , keep him in
half sitting position and offer necessary
medical facility.
Eating , drinking and smoking is strictly
prohibited in area. It is to be kept in cool ,
dry place away from combustible
substance and reducing agents. In case of
spillage collect the content in sealable

13. 7/17/2020