Decontamination Flashcards
Decontamination
or Decon is the process of removing or neutralizing contaminants that have accumulated on workers or equipment.
it is critical to worker health and safety at hazardous waste sites.
Decontamination protects all site personnel and reduces the spread of harmful materials into clean areas and helps prevent the mixing of incompatible chemicals.
Decon protects the community by preventing uncontrolled contaminants from leaving the site
Decontamination Plan
a decontamination plan should be developed before any work begins with hazardous substances on site. The plan is part of the health and safety program. It should include the following:
- establish methods and procedures
- determine appropriate decon methods
- determine number and layout of decon stations
- establish procedures to prevent contamination of clean areas
- determine decon equipment needed
- establish methods of disposing of clothing and equipment
SOP for Decontamination
SOP for Decon - the first step is to develop SOP’s
eg.
- minimize contact with hazardous substances
- use remote sampling
- protect equipment
- wear disposable outer garments
- use disposable equpment
Check PPE Before use
before each use the PPE should be checked to ensure that it doesnt have holes or punctions that would expose skin. Skin injuries such as cuts or scratches may allow penetration into the body by chemicals or infectious agents that directly contact the worker’s skin. particular care should be taken to protect these areas
workers with large areas of damaged skin should not be allowed to work onsite until the skin heals
Proper Dress out procedures
following proper procedures for deressing prior to entering the exclusion zone prevents contaminats for passing through the protective clothing and escape decontamination.
all fasteners zippers, snaps and buttons closed
gloves and boots should be tucked in
hoods should be worn out side the collar
rubber boots to protect the suit feet from tearing
doubling inner gloves
tough outer gloves over the rubber gloves
sleeves should be taped as well as all junctures
more ppe
must include an explanation of equipment selection and use, maintenance, disposal and storage, decontamination and disposal, training and proper fit , donning and doffing, inspection , in use monitoring program, evaluation, and equipment limitations
Training and retraining
all workers should be trained ton SOPs to minimize contact and maximize protection.
if there are any changes to the SOPs workers should be retrained and enforced as long as activities continue at the site
Levels of contamination
contaminants might be on the sureface of the PPE or permeated the material. if they have permeated the material and are not removed by decontamination they can continue to permeate to the inner surface and cause exposure. Surface contaminants are easy to detect and remove but contaminants that have permeated the surface can be difficult or impossible to detect or remove.
the degree of permeation are based on the following factors:
contact time concentration temperature size of contaminant molecules and pore space phjysical state of waste
Permeation factors
contact time. the longer a contaminant is in contact iwth an object the greater probability and extent of permeation. that is why minimizing the contact time is important in a decontamination program.
Concentration and Molecules
molecules flow from high areas of concentration to low areas of concentration. As concentration of wastes increase the possibility of permeation of PPE increases.
disposable ppe should be changed often and never reused.
an increase intemperature generally increases the permeation rate of contaminants
Size of contaminant molecules and pore material
Physical state of waste
permeation increases as the contaminant molecule become smaller and tthe pore space of the material to be permeated increases.
As a rule, gasses vapors and low viscosity liquids tend to permeate more readiloy than high viscosity liquids or solids. it can penetrate thorugh a zipper or around the cuff of a sleeve or pant leg.
seal these areas with tape using chemical resistant tape if desired.
upgrade to a fully encapsulated suit if the vapors are hazardous to the skin.
Decontamination Methods
many factors for decon - 2 facotrs
- if the decon method is effective for the specific chemicals and hazards
- if it poses health and or safety hazard
Methods of decontamination include:
isolation of contaminants
physical removal
chemical removal
Decontamination methods
Methods of decontamination Should either
isolate contaminants (dry decon )
physically remove,
inactivate contaminants by chemical reaction
remove contaminants by physical and chemical means
Isolation of Contaminants
Physical removal
dry decon
this process entails removing contaminated equipment and protective clothing and leaving it in the decontaminated area.
it is the simpliest to set up and it requires the least number of personnel.
physical removal
By rinsing or washing off contaminated areas decontamination can be completed.
contaminants that can be removed by physical means are:
loose contaminants can be removed (dust, and vapors that cling to equipment and workers that can be removed by water or a liquid rinse.)
adhering contaminants - glues cements resins mud have adhesieve properties and are difficult to remove
can be removed by solidyfying liquid or gel contaminants or by rinsing
Chemical removal
washing with cleaning solutions should follow physical removal of contaminants .
Cleaning solutions include
surfactants and
disinfectands that inactivate infectious agents
dry dust can be removed with hepa vacuum and work uniforms laundered in an approved facility
all workers are reuired to shower before leaving the site as well
