1. Chemical and Waste Management
Chapter 23
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 1

2. Chapter 23 Lesson 23.1
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 2

3. Learning Objectives Pronounce, define, and spell the Key Terms.
Describe the potential long-term and short-term effects of exposure to chemicals.
Describe three common routes of chemical exposure.
(Cont’d)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 3

4. Learning Objectives (Cont’d)
Describe the difference between chronic and acute chemical exposure.
Identify four methods of personal protection against chemical exposure.
Describe in general how chemicals should be stored.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 4

5. Introduction
In the day-to-day practice of dentistry, the dental assistant is exposed to a wide variety of chemicals used for treatment procedures, cleaning of instruments and surfaces, disinfection and sterilization, laboratory procedures, and x-ray processing.
The heart, kidney, liver, and lung tissues can be damaged by these chemicals.
Results of exposure range from short-term discomfort (e.g., burns, rashes) to life-threatening conditions (e.g., cancer, sterility, organ failure).
(Cont’d)
What are some examples of items that require special disposal procedures? (Processing solutions for x-rays, lead-foil backing from film packets, scrap dental amalgam.)
The Occupational Safety and Health Administration (OSHA) Hazard Communication Standard was designed to ensure chemical safety in the workplace.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 5

6. Introduction (Cont’d)
For all of the chemicals used in the dental office, it is important for a dental assistant to understand:
Proper use
Proper storage
Proper handling
Proper cleanup of spills
Proper disposal methods
In addition to understanding the proper use, storage, handling, cleanup, and disposal of chemicals, what knowledge should the dental assistant possess? (First-aid procedures associated with chemicals.)
What is the nearest location where dental assistants can find OSHA-approved programs?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 6

7. Hazardous Chemicals
A hazardous chemical is defined as any chemical that has been shown to present either a physical or health hazard.
A hazardous chemical is any substance that:
Can catch fire
Can react or explode when mixed with other substances
Is corrosive
Is toxic
What hazardous chemicals are used in dentistry? (Mercury, powdered natural-rubber latex, disinfectants, nitrous oxide, volatiles from resin-based materials, x-ray chemicals, cleansers, methyl metacrylate monomer, and elastomeric impression materials.)
Which chemical is of greatest concern? (Mercury.)
What serious health consequences could result from exposure to hazardous chemicals?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 7

8. Fig. 23-1 Chemical-hazard warning labels
Fig Chemical-hazard warning labels. (From Stepp CA, Woods MA: Laboratory procedures for medical office personnel, Philadelphia, 1998, Saunders.)
What is the effect of corrosives? (Corrosives can burn and destroy body tissues on contact.)
What materials are considered corrosive?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 8

9. Primary Methods of Chemical Exposure
Gases, vapors, and dusts of chemicals can cause direct damage to the lungs.
Some chemicals are absorbed through the skin.
Eating in an area in which chemicals are used or eating with hands contaminated with chemicals is a common way of ingesting harmful chemicals.
What conditions can exposure cause or contribute to? (Organ damage, respiratory disease, cancer, burns, sterility, dermatitis.)
Which hazardous chemicals are inhaled?
Which are absorbed through the skin?
Which are ingested?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 9

10. Types of Chemical Toxicity
Acute chemical toxicity results from a high level of exposure over a short period. Such exposure is frequently caused by a chemical spill, in which exposure is sudden and a large amount of the chemical in question may be involved.
Chronic chemical toxicity results from many repeated exposures, generally to lower levels, over a much longer time—months or even years.
The difference between acute and chronic toxicity: Acute exposure is of short duration and chronic exposure lasts a long time.
What are signs and symptoms of acute toxicity? (Dizziness, fainting, headache, nausea, vomiting.)
What are the effects of chronic toxicity? (Liver disease, brain disorders, cancer, infertility.)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 10

11. Personal Chemical Protection
Hand protection: When using chemical disinfectants, wear a utility-type glove made from a chemical-resistant material such as natural rubber, neoprene, or industrial-grade nitrile.
Eye protection: Protect the eyes from fumes and splashes while pouring chemicals, such as processing solutions for x-rays, ultrasonic solutions, disinfectants, and sterilants.
Protective clothing: Wear a rubber or neoprene apron when mixing or pouring a chemical.
Inhalation protection: Face masks should be fluid-repellent and provide respiratory protection.
Why are the latex gloves worn during patient care insufficient for the handling of chemicals? (Latex in the glove degrades and creates a sucking action that pulls contaminants and chemicals through the glove and onto the hands.)
What are the three types of eye/face protection? (Safety glasses, face shields, and goggles.)
Because of comfort, ease of use, and appearance, safety glasses are usually preferred over goggles.
For what types of hazardous materials should the dental assistant wear protective clothing? Inhalation protection?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 11

12. Fig Clean-room nitrile gloves provide protection and dexterity in the handling of chemicals. (Courtesy of Lab Safety Supply, Janesville, Wis.)
Keep in mind that gloves are designed as protection against an occasional splash or spill, not for immersion in strong chemicals.
What materials should be used to make gloves that are used by individuals who work with chemicals? Why?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 12

13. Fig. 23-3 Dental assistant wearing chemical goggles.
According to a study published in the Journal of Contemporary Dental Practice, wearing eye protection is the least-practiced infection-control measure.
What are some common causes of damage to the eyes? (Splatters and projectiles, including calculus and debris sent flying during cavity preparation.)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 13

14. Fig This disposable respirator has a tapered angle to fit facial contours around the nose and chin to protect against dusts and chemical mists. (Courtesy of Lab Safety Supply, Janesville, Wis.)
Mist-respirator face masks must be approved by the National Institute of Occupational Safety and Health.
The proper mask should be fluid-repellent and provide respiratory protection.
Under what circumstances should the dental assistant be sure to wear a mist-respirator face mask?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 14

15. Control of Chemical Spills
Accidents and spills should not be common occurrences.
Planning and practice in dealing with such spills should minimize employee exposure to harmful chemicals.
Refer to the material-safety data sheet (MSDS) for the specific product for accurate information on how to manage spills.
What are the primary routes of exposure? (Inhalation, skin contact, and ingestion.)
What information is provided on the MSDS?
For what types of chemicals are MSDSs required?
How would a dental assistant use an MSDS?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 15

16. Mercury-Spill Kits
Mercury-spill kits should be available in all dental offices in which amalgam is used.
Exposure to even small amounts of mercury is very hazardous to the health of dental personnel.
Mercury can be absorbed through the skin or through the inhalation of mercury vapors.
What does a mercury-spill kit contain? (Mercury-absorbing powder, mercury-absorbing sponges, and a disposal bag.)
What are some precautions to take when working with mercury?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 16

17. Fig. 23-5 Mercury-spill kit
Fig Mercury-spill kit. (Courtesy of Lab Safety Supply, Janesville, Wis.)
A mask and utility gloves should be worn during cleanup of a mercury spill.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 17

18. Eye Wash Stations
Occupational Safety and Health Administration (OSHA) regulations require an eyewash unit in every place of employment in which chemicals are used.
A wide variety of styles are available.
When turned on, the eyewash unit will irrigate the eyes with the soft, wide flow of water necessary to bathe away contaminants without causing additional damage.
Employees must be trained in the proper use of the eyewash station, and the unit should be inspected every 3 months to ensure that it is functional.
Emergency eyewash stations provide on-the-spot decontamination and allow workers to flush away hazardous substances that can cause serious injury.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 18

19. Fig A, Countertop eye and eye/face washes provide water to the face and eyes to gently wash away contaminants. (Courtesy of Lab Safety Supply, Janesville, Wis.)
Why do some manufacturers recommend a weekly 3-minute flushing of the eyewash station? (To reduce microbial content in the waterline.)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 19

20. Fig B, A wall-mounted style of eyewash station with a card attached on which to record inspection dates.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 20

21. Ventilation
Good ventilation is a necessity when dealing with any type of chemical.
Many dental offices are equipped with special exhaust systems in the laboratory and sterilization and darkroom areas for fumes and dust.
Radiographic processing chemicals can cause contact dermatitis and irritation of the eyes, nose, throat, and respiratory system because of vapors and fine particles of chemicals.
Why is it important to have good ventilation in a dental office?
Can good ventilation also help reduce incidence of airborne disease?
How can a person tell whether a dental office has good ventilation?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 21

22. Storing Chemicals
All dental materials contain chemicals, and the chemical components in some are more hazardous than others.
When changes in the chemical composition of materials occur, the product may no longer retain its effectiveness.
A basic safe policy is to store dental medications and chemicals in a dry, cool, dark place where they are not exposed to direct sunlight.
The manufacturer’s instructions for storage can be found on the MSDS and should be followed.
What are four key points in storing chemicals? (Follow manufacturer instructions, avoid exposure to light, check expiration date, and rotate inventory.)
What are some guidelines for minimizing exposure to chemical hazards in the dental office?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 22

23. Disposal of Chemicals
Empty containers may hold residues that can burn or explode.
Never fill an empty container with another substance, because a dangerous chemical reaction could occur.
Follow the label and the MSDS for guidance in disposing of empty containers.
What determines whether a substance is a hazardous waste? (Whether it contains certain properties or chemicals that could pose a danger to human health and the environment after being discarded.)
What are the local and state regulations for disposal of hazardous waste?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 23

24. Types of Hazardous Waste
Ignitable waste is flammable or combustible.
Corrosive waste is either highly acidic or basic with a pH less than 2.0 or greater than 12.5, respectively (water has a pH of 7.0).
Reactive waste is chemically unstable or explosive, reacts violently with water, or is capable of giving off toxic fumes when mixed with water.
Toxic waste contains arsenic, barium, chromium, mercury, lead, silver, or certain pesticides.
These types of hazardous waste are listed by the EPA.
Hazardous wastes can contaminate land, air, and water.
What hazardous wastes are commonly generated by dental offices? (Photo-processing wastes [x-ray fixer, developer, and cleaner; x-ray film; lead foils and shields], chemical disinfectants; line-cleaner wastes; universal wastes [batteries, fluorescent lamps, mercury thermometers], amalgam wastes [scrap, capsules, extracted teeth, sludge].)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 24

25. Chapter 23 Lesson 23.2
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 25

26. Learning Objectives
Explain the purpose of the OSHA Hazard Communication Standard.
Explain the recordkeeping requirements of the Hazard Communication Program.
Describe the components of a hazard-communication program.
Explain the purpose of a MSDS.
(Cont’d)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 26

27. Learning Objectives (Cont’d) Create a label for a secondary container.
Identify types of regulated waste generated in a dental office.
Identify types of toxic waste generated in a dental office.
Describe how to package regulated waste for transport.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 27

28. OSHA Hazard Communication Standard
OSHA issued the Hazard Communication Standard because employees have the right to know the identity and hazards of chemicals that they use in the workplace.
The Hazard Communication Standard is also known as the Employee Right-to-Know Law.
It requires employers to implement a hazard communication program.
The OSHA Hazard Communication Standard also ensures that employees know how to protect themselves from the chemicals.
Why is the OSHA Hazard Communication Standard also known as the Employee Right-to-Know Law?
What recordkeeping elements are important? Why?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 28

29. Hazard-Communication Program
Written program
Chemical inventory
MSDS
Labeling of containers
Employee training
The hazard-communication program (HCP) should also address nonroutine tasks and exposure of other personnel, such as outside contractors.
What are the responsibilities of the dental assistant as the coordinator of the office HCP? (Read and understand the OSHA Hazard Communication Standard and implement the written HCP. Compile a chemical inventory, obtain the MSDSs, and update the MSDS file as new products are added to the inventory. Inform other employees of the location of the MSDSs. Also label appropriate containers and provide training to other employees.)
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 29

30. Requirements of the Written Program
Identify the individual who is responsible for the program.
Describe staff training.
Describe how chemicals are handled in the office.
Provide a description of all labeling and safety measures.
Describe how to respond to chemical emergencies such as spills and exposures.
The written program also requires that each individual who is exposed to hazardous chemicals be identified by name.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 30

31. Requirements for the Chemical Inventory
A comprehensive list of every product used in the office is required.
When a new product containing a hazardous chemical is added to the office’s inventory, it must be added to the chemical list, and the MSDS for that product must be placed in the MSDS file.
The manufacturer or distributor must provide an updated MSDS when appropriate.
Several companies offer software and barcode programs that keep track of the chemical inventory, where chemicals are stored, what is in stock, and MSDS information.
What is included in the list of products that contain chemicals?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 31

32. Material Safety Data Sheets
MSDSs contain health and safety information about every chemical in the office.
They provide comprehensive technical information and are a resource for employees working with chemicals.
They describe the physical and chemical properties of a chemical, health hazards, routes of exposure, precautions for safe handling and use, emergency and first-aid procedures, and spill-control measures.
The manufacturers of products that contain hazardous chemicals are required to provide MSDSs.
The MSDSs should be organized in binders.
The MSDS is meant to be an easy reference for information on hazardous substances.
Why are MSDSs so important? (Employees have the right to know what types of substances they are working with and how to safely handle them.)
What are the nine sections of an MSDS?
What information is included in each section?
What is a good way to store MSDSs?
Why are storage and accessibility of MSDSs important?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 32

33. Fig. 23-8 MSDSs for quality-control recordkeeping.
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 33

34. Requirements for Employee Training
Staff training is required:
When a new employee is hired
When a new chemical product is added to the office
Once a year for all continuing employees
Records of each training session must be kept on file.
Training records are to be retained for at least 5 years.
What areas must be included in the chemical training program? (The use of hazardous materials, all safety practices, including all warnings, required PPE, safe handling and disposal methods.)
Why is it important to train employees in the use and disposal of hazardous chemicals?
What is included in a hazard communication training program?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 34

35. Labeling of Chemical Containers
The label must contain:
The identity of the hazardous chemical(s)
The name and address of the manufacturer or responsible party
Appropriate warnings
The National Fire Protection Association has a labeling system that is frequently used to label containers of hazardous chemicals.
What are the colors of the four diamonds, and what does each represent? (Blue, health hazard; red, flammable; yellow, reactivity; white, special hazard symbols.)
Is this an effective labeling system? Why or why not?
What are the types of dental waste? How should each be labeled?
Copyright © 2009, 2006 by Saunders, an imprint of Elsevier Inc. All rights reserved. 35