This month our example is
Acrylonitrile, which has a chemical formula of
CH2=CHCN. Acrylonitrile is a clear, colorless
or slightly yellow liquid that is highly volatile and
toxic. Acrylonitrile vapor is heavier than air. It has a
pungent odor of onion or garlic that but the odor
detection level is at a concentration level that does
not provide adequate warning of hazardous levels.
Acrylonitrile is poisonous by inhalation, ingestion or
skin contact. Within the body acrylonitrile releases
It is a health hazard because of its
toxicity and it is flammable forming mixtures with air
that are flammable or explosive. It is shipped as a
liquid, since it has a boiling point of 171°F. It is
moderately soluble in water (solubility in water is 7.45
g/100 ml) and soluble in most organic solvents.
Acrylonitrile, one of the world’s
most important industrial chemicals, is produced by
catalytic reaction of propylene with ammonia. In 1999,
it was reported that approximately 80 plants in 22
countries produce about 10 billion pounds of
acrylonitrile each year. It is a raw material in
the manufacture of acrylic fibers, styrene plastics, and
adhesives. Such fibers and plastics are components of
clothing, furniture, appliances, construction materials,
motor vehicles, and food packaging. In the past,
acrylonitrile was also used as a room fumigant and
pediculicide (an agent used to destroy lice).
Synonyms include AN, cyanoethylene,
propenenitrile, VCN, vinyl cyanide, carbacryl, fumigain,
and ventox. Acrylonitrile reacts with strong oxidizers,
acids, alkalies, bromine, amines, and copper. Unless
inhibited (usually with methylhydroquinone),
acrylonitrile may polymerize spontaneously. It may also
polymerize when heated or in the presence of strong
OSHA PEL (permissible exposure limit)
= 2 ppm (skin) (averaged over an 8-hour workshift).
OSHA STEL (short-term exposure limit)
= 10 ppm (over a 15-minute time period).
NIOSH IDLH (immediately dangerous to
life or health) = 85 ppm.
AIHA ERPG-2 (maximum
airborne concentration below which it is believed that
nearly all persons could be exposed for up to 1 hour
without experiencing or developing irreversible or other
serious health effects or symptoms that could impair
their abilities to take protective action) = 35 ppm.
Exposure --Some, but not all, of the toxicity of
acrylonitrile may be due to the metabolic release of
cyanide, which inhibits numerous enzymes, including
cytochrome oxidase, resulting in cellular asphyxiation.
Toxicity not related to cyanide formation is due to the
formation of reactive vinyl groups and epoxide
intermediates which can deplete glutathione stores and
cause liver damage. The onset of symptoms due to cyanide
release may be delayed 4 to 12 hours.
not always respond to chemicals in the same way that
adults do. In addition, children of different ages
(e.g., inutero, infants, toddlers, older
children) may have different responses to certain
chemical exposures, and thus, different protocols for
managing their care may be needed.
Acrylonitrile has a boiling point of
171°F and a melting point of -116°F. Its molecular
weight is 53, and has a relative vapor density is 1.9
(compared to air), so it will seek low areas. It has a
vapor pressure of 83 mm Hg at 68°F (0.11 atmosphere).
The lower Explosive Limit (LEL) is 3%; the Upper
Explosive Limit (UEL) is 17%.
The important thing to remember when
dealing with Acrylonitrile is that it is both a very
flammable substance and its vapors are toxic. Therefore
if the material is released from its container, every
effort should be made to eliminate ignition sources and
appropriate PPE must be worn to protect from exposure or
- Keep away from heat and flame. Keep away from
sources of ignition. Store in a tightly closed
container. Store in a cool, dry, well-ventilated area
away from incompatible substances. Flammables-area.
- Wash thoroughly after handling. Wash hands before
eating. Remove contaminated clothing and wash before
reuse. Use only in a well ventilated area. Ground and
bond containers when transferring material. Use
spark-proof tools and explosion proof equipment. Do not
get in eyes, on skin, or on clothing. Empty containers
retain product residue, (liquid and/or vapor), and can
be dangerous. Do not ingest or inhale. Do not
pressurize, cut, weld, braze, solder, drill, grind, or
expose empty containers to heat, sparks or open flames.
- Eyes: Wear appropriate protective eyeglasses or
chemical safety goggles as described by OSHA's eye and
face protection regulations in 29 CFR 1910.133 or
European Standard EN166. Skin: Wear appropriate
protective gloves to prevent skin exposure. Clothing:
Wear appropriate protective clothing to prevent skin
- Follow the OSHA respirator regulations found in
29CFR 1910.134 or European Standard EN 149. Always use a
NIOSH or European Standard EN 149 approved respirator
spills or leaks - Absorb spill with inert material,
(e.g., dry sand or earth), then place into a chemical
waste container. Avoid runoff into storm sewers and
ditches which lead to waterways. Clean up spills
immediately, using the appropriate protective equipment.
Scoop up with a nonsparking tool, then place into a
suitable container for disposal. Remove all sources of
ignition. Provide ventilation. Use water spray to reduce
vapors or divert vapor cloud drift.
- Stable under normal shipping and handling
conditions. However, it may undergo explosive
polymerization if uninhibited.
- Oxidizing agents, acids, bases, copper, copper
alloys, heat, light, bromine, silver nitrate, benzyl
trimethylammonium hydroxide, peroxides.
Decomposition - Hydrogen cyanide, nitrogen oxides,
carbon monoxide, carbon dioxide.
hazards - Not corrosive to metals.
related information - Exposure effects
May cause cancer in humans.
Prolonged skin contact results in systemic toxicity and
ulceration after a latency period of several hours with
the affected skin resembling a second degree thermal
- Harmful if swallowed. Symptoms may include:
headache, excitement, fatigue, nausea, vomiting, stupor,
- May be fatal if inhaled. Inhalation of high
concentrations may cause central nervous system effects
characterized by headache, dizziness, unconsciousness
and coma. May cause cyanosis, characterized by
bluish-colored skin. May cause irritation of the
respiratory tract with burning pain in the nose and
throat, coughing, wheezing, shortness of breath and
pulmonary edema. Exposure to high concentrations may
cause weakness, asphyxia, and death.
- Causes skin irritation. Harmful if absorbed
through the skin. May cause skin sensitization, an
allergic reaction, which becomes evident upon
re-exposure to this material. Prolonged and/or repeated
contact may cause defatting of the skin and dermatitis.
It is toxic in contact with skin.
- Causes severe eye irritation. May result in
corneal injury. Lachrymator. Causes redness and pain.
- Do NOT induce vomiting. If victim is conscious and
alert, give 2-4 cupfuls of milk or water. Never give
anything by mouth to an unconscious person. Get medical
- Get medical aid immediately. Remove from exposure
to fresh air immediately. If breathing is difficult,
give oxygen. DO NOT use mouth-to-mouth respiration. If
breathing has ceased apply artificial respiration using
oxygen and a suitable mechanical device such as a bag
and a mask.
- Get medical aid immediately. Immediately flush
skin with plenty of soap and water for at least 15
minutes while removing contaminated clothing and shoes.
- Immediately flush eyes with plenty of water for at
least 15 minutes, occasionally lifting the upper and
lower eyelids. Get medical aid immediately.
In using the PEAC application we
access information for the chemical by first locating
Acrylonitrile in the database. The following figures
show the screens displayed for chemical properties,
Figure 2 for the PEAC-WMD for Windows application
and Figure 3-6 for the PEAC‑WMD for the Pocket PC
Figure 2 - Using the Lookup By: Name for
Acrylonitrile using the PEAC-WMD for Windows
Review of the information displayed
in the chemical properties screen whether in Figure 2
(above) or Figures 3-6 (below), show chemical properties
values discussed earlier at the top of this discussion.
As you can see, the published toxicity values, e.g.,
IDLH, ERPGs (Emergency Response Protection Guidelines)
published by American Industrial Hygiene Association,
and the TEELs (Temporary Emergency Exposure Limits)
published by Department of Energy are provided. We will
use the IDLH as the Level of Concern when we develop the
PAD a little later.
Figure 3 – Selecting
Acrylonitrile using the PEAC-WMD for Pocket PC
Figure 4 – The top portion of
the Chemical Properties Data Display
Figure 5 – The middle portion
of the Chemical Properties Data Display
Figure 6 – The lower portion
of the Chemical Properties Data Display
The PEAC-WMD application provides
more than just the Chemical Properties for the
identified material, the Chemical Properties are
just the default information screen displayed, by
clicking (if running the Windows version, see Figure 7)
or tapping (if running the Pocket PC version, see Figure
8) on the drop-down box where Chemical Properties
is displayed on the screen, the user is provided with a
list of other databases that provide information for the
selected chemical (Acrylonitrile in our current
example). So the search is done once, and the user is
indexed into the different databases easily and quickly.
Figure 7 – Accessing other
databases from the PEAC-WMD for Windows
Figure 8 – Accessing other
databases from the PEAC-WMD for Pocket PC
A quick review or sampling of the
type of information available in each of these screen is
now provided. First is access to Respirators
Recommendations, these are primarily taken from the
NIOSH Pocket Guide and provide the user with different
types of respirators for increasing concentrations. A
sample of the information is provided in Figure 9.
Likewise the Chemical Protective Clothing (CPC)
database can be accessed by clicking on either the
All Chemical Protective Clothing or the
Available Chemical Protective Clothing selection
as shown in Figure 10. The All Chemical Protective
Clothing displays all the CPC entries in the
PEAC‑WMD database for the selected chemical vs. the
Available Chemical Protective Clothing displays
just those CPC entries that match the manufacturers the
user has previously identified as the products the
response organization typically keeps in inventory.
Figure 9 – Respirator
Recommendations for Acrylonitrile
Figure 10 – Chemical
Protective Clothing for Acrylonitrile
The IC (Incident Commander) will
typically utilize more than a single resource for
developing a response plan but sometimes the information
in other resources will use a different name for the
same substance. Clicking on the Synonyms
selection will provide a quick list of other names
the substance may be referenced by in other resources as
shown in Figure 11. To further assist the responder in
initiating the best response plan, PEAC‑WMD also
provides the generic guidelines found in the ‘orange
pages’ of the DOT Emergency Response Guidebook (ERG).
These are categorized into different types of procedures
depending on the incident and the problem to be
mitigated. An example for Spill or Leak Response
is shown in Figure 12.
|Figure 11 - Synonyms
||Figure 12 – ERG Spill or Leak
A benefit of using the PEAC tool is
assistance in the development of an evacuation zone for
those chemicals that produce a toxic vapor cloud.
Acrylonitrile will be released from a container as a
liquid, but it has a vapor pressure of 83 mm Hg at room
temperature and will readily evaporate into the air. As
with all of our examples, AristaTek creates a scenario
for a spill or release of the specific chemical, and
then we work through the development of a PAD
(Protective Action Distance) to demonstrate how the PEAC
system works. For our scenario using Acrylonitrile as
the spilled chemical we’ll set the location to be on the
outskirts of Raleigh, NC and the time as 4:00 AM on May
15th. A railcar of Acrylonitrile on the Norfolk Southern
Railroad has been involved in an accident just off US
Highway 70 and I-40. There is a 2-3” hole in the
railcar, with a liquid pool being formed that is
approximately 150’ in diameter. The temperature is about
70°F, the winds are about 2 mph, and it’s a clear night
(no clouds). This is a wooded area with residential and
commercial areas nearby and light traffic on the nearby
As seen at the top of the data
display screens, there is a yellow icon displayed; this
is the PEAC icon for notifying the user that a
Protective Action Distance can be calculated. Clicking
or tapping on the PAD icon will display a screen as
shown in Figure 13. Following through the screens, we
provide information on the Meteorology, Container Size,
and Type of Release (Source). The last screen displays
the PAD based on the provided information. If you decide
to follow along on this example, remember to change the
location to Raleigh and the time to 4:00 AM, May
It’s Raleigh in May and the
temperature about 70°, light wind is set for 2
mph, clear sky so we’ll set cloud cover to 0%, and
the terrain is Urban/Forest since it’s an urban
We have selected from our list
of container sizes the Railcar selection.
This provides us with a default size that should
get us pretty close to the actual size.
Since the scenario has a 2-3”
hole, we’ve selected a Hole or Pipe Release
as the Source type of release and
specified the size of the liquid pool.
Figure 13 – Calculating a PAD using
the PEAC‑WMD System
By pressing the right arrow at the
top of the screen, the PEAC system will display a screen
as shown in Figure 14. This calculates a PAD
(Protective Action Distance) based on the default
Level of Concern the IDLH of 85 ppm. This
evacuation or standoff distance is based on the toxicity
of Acrylonitrile, not its flammability. Since it is
flammable, care needs to be given to ignition sources in
the immediate vicinity of the release.
Figure 14 – Default PAD for
Acrylonitrile using the IDLH of 85 ppm
Clicking or tapping on the pop up
list for the Level of Concern a list of published
toxicity values for Acrylonitrile is displayed. Clicking
or tapping on the ERPG-2 value of 35 ppm (Figure 15) and
will allow the PEAC tool to recalculate a PAD for the 35
ppm concentration Level of Concern. In our
example the PAD for the 35 ppm concentration is
displayed (Figure 16).
Figure 15– Selecting another Level
Figure 16 – PAD for ERPG-2 (35
Portions of this discussion were
adapted from the WEB site supported by the Hardy
Research Group, Department of Chemistry, The University
of Akron: http://ull.chemistry.uakron.edu/. Additional
information was adapted from the web site provided by
International Programme on Chemical Safety (IPCS) INCHEM
site located at: http://www.inchem.org/.
Additional information was also adapted from the Agency
for Toxic Substances and Disease Registry (ATSDR) Web
site for Medical Management Guidelines at: http://www.atsdr.cdc.gov/.