A noise training exercise for drillers,

helpers, and anyone exposed

to loud noise from a drill rig

A noise training exercise for drillers, 

helpers, and anyone exposed 

to loud noise from a drill rig

Drill Rig Incident

Workplace 

Safety and Health

Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

IC 9473

Information Circular/2005
Information Circular 9473 

Drill Rig Incident 

By Edward A. Barrett and Roberta A. Calhoun 

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 

Centers for Disease Control and Prevention 

National Institute for Occupational Safety and Health 

Pittsburgh Research Laboratory 

Pittsburgh, PA 

February 2005 
ORDERING INFORMATION 

Copies of National Institute for Occupational Safety and Health (NIOSH) 

documents and information 

about occupational safety and health are available from 

NIOSH–Publications Dissemination 

4676 Columbia Parkway 

Cincinnati, OH 45226–1998 

 FAX 513–533–8573 

 Telephone: 1–800–35–NIOSH 

 (1–800–356–4674) 

 E-mail: pubstaft@cdc.gov 

 Web site: www.cdc.gov/niosh 

This document is in the public domain and may be freely copied or reprinted. 

____________________________________ 

Disclaimer: Mention of any company or product does not constitute endorsement by NIOSH. 

DHHS (NIOSH) Publication No. 2005–108 
Table of Contents 

Introduction 1 

Acknowledgment 1 

Exercise summary 2 

How to use the exercise 3 

Performance objectives 4 

Master answer sheet for Drill Rig Incident 5 

Instructor=s discussion notes 9 

Scoring key 15 

Summary of field test results 16 

Answer key for pretest / posttest questions 19 

Appendices 

Appendix A: Problem booklet (duplicate this copy for use in class) 

Appendix B: Blank answer sheets (print the invisible ink answers on this) 

Appendix C: Invisible ink answers (print these on the answer sheet) 

Appendix D: Pretest / posttest questions 
Drill Rig Incident 

1

DRILL RIG INCIDENT 

By Edward A. Barrett1 and Roberta A. Calhoun2

Introduction 

This Instructor=s Copy contains most of the materials trainers will need in order to use 

Drill Rig Incident (DRI). It includes suggestions for using the exercise, performance 

objectives for the training, master answer sheets, a scoring key, and a set of discussion 

notes that provides additional subject information. Four appendices are also included. 

Appendix A is the complete exercise problem booklet. It may be reproduced so that 

every person in the training class has one. Appendix B contains answer sheet blanks. 

The blanks are furnished if you choose to have the invisible ink answers that appear in 

appendix C printed on them at your location.3 Answer sheets are consumable. One is 

needed for each group of three to five persons who work the exercise together. An 

alternative is for each individual trainee to have his/her own answer sheet. Appendix D 

contains the 24-question pretest / posttest that was used in the field evaluation of the 

DRI exercise. 

Acknowledgment 

The authors thank Linda J. McWilliams, Statistician, NIOSH Pittsburgh Research 

Laboratory, for her assistance in analyzing the experimental data in this document. 

 

1

Mining engineer. 

2

Safety and occupational health specialist. 

Pittsburgh Research Laboratory, National Institute for Occupational Safety and Health, Pittsburgh, PA. 

3

You can do this yourself if you have the proper equipment, or you can contact a local printer. 
Drill Rig Incident 

2

Exercise Summary 

The following summary information is provided to help you decide if this exercise is 

appropriate for your training class. 

Type: Invisible ink 

Length: Eleven questions (20 minutes for administration plus varying times for 

followup discussion) 

Skills: Recognizing basic facts about noise, hearing loss, and hearing protection 

 Identifying ways to protect hearing 

 Wearing hearing protection properly 

Location: Surface drill site 

Problem: You are the drill crew foreman. At the beginning of the day shift, your 

helper latches the breakout wrench around the first pipe section as you 

begin to remove rod sections from a drill hole. Your helper is supposed to 

step back at this point in case the wire rope holding the wrench should 

break. He doesn=t step back on his own and also fails to respond to you 

shouting at him to step back. In a split second, you must decide what 

to do. 

There is a related training exercise available entitled Wearing Hearing Protection 

Properly: A 3-D Training Aid for Drillers, DHHS (NIOSH) Publication No. 2005–107 

(IC 9472). It can be obtained by contacting NIOSH at: 

Telephone: 1–800–35–NIOSH (1–800–356–4674) 

Fax: 513–533–8573 

E-mail: pubstaft@cdc.gov 

www.cdc.gov/niosh 
Drill Rig Incident 

3

How to Use the Exercise 

1. Look at the performance objectives on the next page. Decide if the exercise is 

appropriate for your training needs. 

2. Work through the exercise using the developing pen and score your responses. 

3. Review the master answer sheet. Look at all of the answers, both correct and 

incorrect. 

4. Study the Instructor=s Discussion Notes for the exercise. 

5. Become thoroughly familiar with the problem so that you can present it to your class 

without reading it. 

6. When you present the exercise to your class: 

• Give each person an exercise problem booklet, and give each group of three to five 

persons an answer sheet and a developing pen.4

• Go over the instructions for the exercise. 

• Demonstrate how to select and mark answers using the developing pen. 

• Explain the problem, making sure that everyone understands the situation. 

• Have the class work the exercise. 

• When class members finish, ask them to figure their scores using the instructions at 

the end of the exercise. 

• After everyone in the class has finished, review the exercise. Discuss why certain 

answers are correct and why others are incorrect.5

 Add your own ideas. 

 

4

An alternative would be to give each person in the class an answer sheet and developing pen in addition 

to the problem booklet. 

5

Regardless of whether the exercise is completed by a small group of trainees or an individual, class 

discussion is an important followup to the training. 
Drill Rig Incident 

4

Performance Objectives 

Objective Capability Description of required performance and conditions 

Number Verb(s) under which it is to occur 

1. DR6 Recall The initial action in the event of an emergency should 

 Apply always be to shut down the rig using a kill switch 

2. HL Recall Basic facts about individual hearing loss 

3. HL Recognize The signs that workers should use to determine if they have 

 a hearing loss 

4. HL Recall The personal and job-related benefits of protecting the 

 hearing that workers have left 

5. N Identify Conditions in the workplace indicating that surrounding 

 noise levels are too loud 

6. N Apply Procedures and practices that may be used to deal with 

 loud noise coming from drill rigs 

7. HP Recall Procedures for wearing hearing protection properly 

 Apply 

 

6

Skill and knowledge domain abbreviations: 

 DR = Drill rig safety 

 HL = Hearing loss 

 HP = Hearing protection 

N = Noise 
Drill Rig Incident 

5

Master Answer Sheet for Drill Rig Incident

Use this answer sheet to mark your selections. Rub the developing pen gently and 

smoothly between the brackets. Don't scrub the pen or the message may blur. Be sure 

to color in the entire message once you have made a selection, otherwise you may not 

get all the information you need. The last part of the message will tell you what to do 

next. 

Question A (Choose only ONE unless you are told to "Try again.") 

1. [ This is not the first thing that needs to be done. Try again. ] 

2. [ This is not the first thing that needs to be done. Besides, you don’t want to ] 

 [ cause Vinny to look away from the drill. Try again. ] 

3. [ You know that wire ropes have been known to snap. You should do ] 

 [ something now. Try again. ] 

4. [ Correct. You need to stop the rig before Vinny gets hurt. Do the next ] 

 [ question. ] 

Question B (Choose only ONE unless you are told to "Try again.") 

5. [ There was no apparent injury, but for Vinny’s sake something should be ] 

 [ done. Try again. ] 

6. [ This isn’t important right now. You will probably learn why the rope broke ] 

 [ later on. Try again. ] 

7. [ Correct. For Vinny’s protection in case any medical problems develop later, ] 

 [ the safety manager will need to have some record of the incident. Do the ] 

 [ next question. ] 

8. [ Finding someone to blame is not important. Try again. ] 

9. [ You need to do something else first. Try again. ] 

Question C (Select as MANY as you think are correct.) 

10. [ Finding someone to blame isn’t going to help the situation. ] 

11. [ Correct. Since no one got hurt he wants to learn the details before anyone ] 

 [ forgets what happened. ] 

12. [ Correct. He may be able to prevent similar incidents by developing SOPs ] 

 [ and safety or toolbox meetings using this information. ] 

13. [ Correct. It is often possible to develop safer ways to complete a task by ] 

 [ looking at details of previous incidents. ] 
Drill Rig Incident 

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Question D (Select as MANY as you think are correct.) 

14. [ Even though the weather was foggy, the distance between you and Vinny ] 

 [ was so close that visibility was not a problem. ] 

15. [ Correct. The usual work practice is for your helper to back away as soon ] 

 [ as he puts the wrench on a rod section. ] 

16. [ Correct. This is an obvious factor that led to the incident. ] 

17. [ Correct. He stayed there because he didn’t follow your directions to move ] 

 [ back. ] 

18. [ Even though drill rigs are noisy, Vinny should have been able to hear your ] 

 [ directions. ] 

Question E (Choose only ONE unless you are told to "Try again.") 

19. [ Vinny would have been able to hear you shouting even if he was wearing foam ] 

 [ ear plugs. Try again. ] 

20. [ Vinny knows the dangers in drilling, so he was probably paying very close ] 

 [ attention. Try again. ] 

21. [ Vinny has enough experience around drill rigs to know that wire ropes can ] 

 [ break. Try again. ] 

22. [ Correct. If Vinny has a hearing loss, this would explain why he didn’t hear your ] 

 [ original instructions or your shouting. Do the next question. ] 

Question F (Select as MANY as you think are correct.) 

23. [ Correct. Once your hearing is lost, it will never come back. ] 

24. [ Our ears don’t adjust to loud noise; we just lose our ability to hear normal ] 

 [ sounds. ] 

25. [ Correct. Damage to a person’s hearing cannot be reversed. ] 

26. [ Correct. There are a number of things a person can do to prevent ] 

 [ hearing loss. ] 

27. [ There is no way to “cure” hearing loss. Hearing aids can help some people, ] 

 [ but not everyone can be helped by a hearing aid. ] 

28. [ Correct. Stress can develop in persons who have lost some of their hearing ] 

 [ because communication becomes difficult. ] 

29. [ Permanent hearing loss can develop very quickly if noise levels are high. ] 
Drill Rig Incident 

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Question G (Select as MANY as you think are correct.) 

30. [ Correct. If this happens most of the time, it’s one sign that a person may ] 

 [ have a hearing loss. ] 

31. [ This doesn’t necessarily mean that they have a hearing problem. A loud ] 

 [ voice may be normal for some people. ] 

32. [ Correct. In most cases, this indicates a hearing loss. ] 

33. [ Correct. With a hearing loss, it is difficult to hear all of the sounds that are ] 

 [ spoken. Conversation may sound like people are mumbling. ] 

34. [ Correct. Called tinnitus, this is a classic symptom of hearing loss. ] 

35. [ Correct. ] 

Question H (Select as MANY as you think are correct.) 

36. [ Correct. Loud noise often causes physical pain in a person’s ears. ] 

37. [ Correct. Some call this the “2-foot rule,” and it’s a good way for drillers and ] 

 [ other workers to realize that noise in their workplace is too loud. ] 

38. [ Correct. Noise is too loud if you can’t hear someone talking from 2 feet ] 

 [ away. ] 

Question I (Select as MANY as you think are correct.) 

39. [ This will not contribute to noise reduction. ] 

40. [ Correct. Getting away from drill rig noise for short periods of time will help to ] 

 [ reduce their total exposure time during a shift. ] 

41. [ Correct. It’s possible that some type of control can be used to reduce ] 

 [ drill rig noise levels or time of worker exposure to noise. ] 

42. [ Correct. This is a sure way to protect a person’s hearing. ] 

43. [ Noise from other equipment just adds to the total noise level and would only ] 

 [ make matters worse. ] 

44. [ Correct. This is a reminder to all workers that noise levels are high and that ] 

 [ everyone should be using hearing protection. ] 
Drill Rig Incident 

8

Question J (Select as MANY as you think are correct.) 

45. [ Correct. Any growth of beard or sideburns will affect the seal and is ] 

 [ discouraged. ] 

46. [ Correct. This makes the ear plugs thinner so they can be inserted into ] 

 [ your ear canal. ] 

47. [ Correct. This will straighten out the ear canal and make it easier to insert ] 

 [ the plug. ] 

48. [ You need to use your finger to keep it in place in the ear canal while it ] 

 [ swells up. ] 

49. [ Correct. Combining both types of hearing protection should be done only for ] 

 [ very loud noise. ] 

50. [ Dirty ear plugs do not give the same protection as clean ones. There is ] 

 [ also a danger of infection. Dirty ear plugs should be thrown away and ] 

 [ replaced with new ones. ] 

Question K (Select as MANY as you think are correct.) 

51. [ Correct. ] 

52. [ Correct. ] 

53. [ Correct. ] 

54. [ Correct. Although hearing aids may help, they can never bring back ] 

 [ normal hearing. ] 

Finding your score 

Number of "Correct" answers you colored in = (1) __________ 

21 minus number of incorrect answers you colored in = (2) __________ 

Add (1) and (2) to get your total score = (3) __________ 

Highest possible score = 54 

Lowest possible score = 0 
Drill Rig Incident 

9

Instructor=s Discussion Notes 

General Information

Use the information presented here, along with your own ideas, to discuss the exercise 

with the class after it is completed. Group discussion will help strengthen knowledge 

and skills learned by relating the subject material in the exercise to the background and 

experiences of workers. Trainees generally enjoy discussing the answers, and in doing 

so, they often suggest other appropriate responses based on their experience. The 

purpose of Drill Rig Incident is to teach workers about noise, hearing loss, and hearing 

protection. Reviewing answers can contribute to this goal by focusing on the interests 

and needs of trainees. 

It is often helpful to review the exercise by showing overhead transparencies of all 

answers while workers follow along in their problem booklets. This allows you to lead 

the group through the exercise and to discuss both correct and incorrect responses to 

each question. Overheads of all answers can be made using the master answer 

sheets, which begin on page 5. 

The following discussion notes provide additional information for your use. Read 

through and think about the notes before the training class. Incorporate the information 

you find here with your own knowledge, and make these points at the appropriate 

places in the followup discussions. 

Special Emphasis Questions

After field tests were completed in the evaluation phase of Drill Rig Incident, it was 

noted that of the 54 total responses to the 11 questions (A through K), 6 were 

incorrectly identified by a high percentage of trainees. One of the six is a correct 

answer that should have been revealed using the developing pen, but was not. The 

other five are incorrect answers that should not have been revealed, but were. It is 

recommended that the instructor place additional emphasis on these six responses 

during class discussions. Additional information is provided for this purpose in the next 

section. 

Question D

18. Loud drill rig noise. 

 [ Even though drill rigs are noisy, Vinny should have been able to hear your ] 

 [ directions. ] 

Question E 

20. Vinny wasn’t paying attention. 

 [ Vinny knows the dangers in drilling, so he was probably paying very close ] 

 [ attention. Try again. ] 
Drill Rig Incident 

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Question F 

29. Hearing loss develops after many years of exposure to loud noise. 

 [ Permanent hearing loss can develop very quickly if noise levels are high. ] 

Question G 

31. Someone tells them they talk too loud. 

 [ This doesn’t necessarily mean that they have a hearing problem. A loud ] 

 [ voice may be normal for some people. ] 

Question J 

45. Keep beards or long sideburns trimmed so they don=t affect the seal of earmuffs. 

 [ Correct. Any growth of beard or sideburns will affect the seal and is ] 

 [ discouraged. ] 

48. After placing the rolled and squeezed ear plug in your ear, release it. It will expand 

to give you a snug fit. 

 [ You need to use your finger to keep it in place in the ear canal while it ] 

 [ swells up. ] 

Discussion

Question A – The correct answer is 4. The best action to take at this point is to hit a kill 

switch. The wire rope holding a wrench can break. According to the Occupational 

Safety and Health Administration (OSHA), a fatality occurred in 1989 when a worker 

was hit by a drill rig pipe tong (wrench) handle that rotated freely after the wire rope, 

to which it was attached, snapped. An OSHA investigation found that one of the factors 

causing the incident was that the wire rope snub line was too long. Workers around a 

drill rig must know where kill switches are located and not hesitate to use them in case 

of an emergency. 

Question B – The correct answer is 7. Most of the test subjects answered this question 

correctly. It is wise, and very often company policy, to inform someone responsible for 

employee safety as soon as possible after an incident occurs. 

Question C – The correct answers are 11, 12, and 13. All of these are reasons that a 

safety manager should talk with workers after an incident. Gathering information from 

those involved will generally yield valuable insight that can be used in a variety of 

constructive ways. Workers should be reminded that a safety manager=s function is not 

to lay blame. Pointing a finger doesn’t solve problems. At this point, he doesn’t know 

what the problem is, and it is his responsibility to find out. 
Drill Rig Incident 

11

Question D – The correct answers are 15, 16, and 17. These are somewhat common 

factors that contribute to many workplace incidents, and they clearly played a role here. 

It was stated in the background information that the weather is cool and foggy; however, 

the driller and helper generally work in such close proximity that one would not expect 

fog to be a problem (14). 

More than two-thirds of the test subjects also chose 18 as one of the correct responses: 

18. Loud drill rig noise. 

 [ Even though drill rigs are noisy, Vinny should have been able to hear your ] 

 [ directions. ] 

A common practice at drill sites is to communicate by shouting above the noise 

produced by running equipment, in this case a drill rig. Loud noise is routine and 

therefore should not be considered a factor contributing to Vinny=s incident. 

Question E – The correct answer is 22. Two things occurred early on that indicate the 

communication breakdown between the driller and Vinny could have been due to 

Vinny=s hearing loss. Vinny was reminded by his driller to “step back after you attach 

the automatic chuck,” and after he latched the breakout wrench around the first pipe 

section, his driller shouted the word “back” to him. Vinny, an experienced drill rig 

worker, didn’t heed either warning because he didn’t hear them. Vinny wasn’t wearing 

any type of hearing protection and, even if he had been using foam ear plugs, he still 

should have been able to hear someone shouting at him (19). 

More than half of the test subjects chose 20 as the correct answer: 

20. Vinny wasn’t paying attention. 

 [ Vinny knows the dangers in drilling, so he was probably paying very close ] 

 [ attention. Try again. ] 

Because Vinny has 5 years of experience on a drill crew, he was probably paying close 

attention to what he was doing. Also, because of his experience, it is likely that Vinny is 

aware that wire ropes holding a breakout wrench can snap (21). 

Question F – The correct answers are 23, 25, 26, and 28. Hearing loss is permanent 

(23). Exposure to loud noise can result in what may seem to be a temporary loss of 

hearing. Even though hearing seems to return to “normal” after a brief period of time, 

some small loss actually occurs. Loud noise damages the hair cells and nerves in the 

inner ear, which cannot be replaced or repaired. Exposure to multiple short, loud noises 

adds up and eventually results in permanent damage, similar to what happens from 

continuous exposure. 

The understanding that hearing loss is permanent is the main reason to protect hearing 

at all times, both at the workplace and away from it. Hearing loss is preventable (26). 

Even if some hearing has been lost, the remaining hearing needs to be protected. 

Some hearing is better than none at all. Once hearing is lost, it is gone forever and 

cannot be reversed (25). There is no known way to “cure” hearing loss (27). Damaged 

hair cells and nerves cannot be repaired and returned to normal. 
Drill Rig Incident 

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Our ears never adjust to loud noise (24). It may seem that a noise doesn’t sound quite 

as loud as it once did, but this is because some of our ability to hear it has been lost, not 

because our ears have adjusted to it. 

Hearing loss can result in stress. This is one of the consequences of hearing loss that 

is not well-known. People with a hearing loss develop stress because of their inability to 

hear some, or all, of what others are saying. 

More than half of the test subjects chose 29 as a correct answer: 

29. Hearing loss develops after many years of exposure to loud noise. 

 [ Permanent hearing loss can develop very quickly if noise levels are high. ] 

Trainees should be reminded that (1) loud noise can damage the ears instantly, 

(2) continuous exposures can cause a similar hearing loss over a period of time, and 

(3) age has nothing to do with (1) or (2). 

Question G – The correct answers are 30, 32, 33, 34, and 35. It is important for 

workers to be able to assess their own level of hearing. They are more likely to protect 

the hearing they have left when they know and accept the fact that some of their 

hearing is gone. Workers need to be aware that one sign of a hearing loss is asking 

others to repeat what has been said (30). Problems hearing normal conversation (32), 

complaints about people mumbling (33), and turning up the TV volume (35) are also 

signs of hearing loss. Constant buzzing or ringing in the ears, called tinnitus (34), can 

also indicate a hearing loss. 

Nearly three-fourths of the test subjects chose 31 as a correct answer: 

31. Someone tells them they talk too loud. 

 [ This doesn’t necessarily mean that they have a hearing problem. A loud ] 

 [ voice may be normal for some people. ] 

If someone talks too loud, it could be because they have a hearing loss. However, 

it could also be that the person’s voice is normally loud. 

Question H – The correct answers are 36, 37, and 38. Loud noise in modern society 

has become common, and we often accept it without concern. We should become 

familiar with simple techniques for judging if noise is too loud, particularly in the 

workplace, but away from it as well. Any noise that causes pain in the ears (36) is too 

loud. A good practice at drill sites is the 2-foot rule. Noise is too loud if you can’t hear 

someone who is standing 2 feet away talking to you (37). From any reasonably close 

distance, however, if you must shout to be heard, then the surrounding noise is too 

loud (38). 

Question I – The correct answers are 40, 41, 42, and 44. Certain administrative 

controls that conform to company policy and, with respect to exposure time, to current 

OSHA noise standards can be used to deal with loud noise around the drill rig. For 

example, individual time spent in high noise areas can be reduced by rotating workers in 

and out of noisy locations and by telling workers not to linger around the running drill 

head or compressor areas during lulls in work activity (40). Implementing certain 

engineering controls may help to reduce drill rig noise levels (41). Examples of the 

latter may include mufflers and reduced machine vibration. 
Drill Rig Incident 

13

Workers need to protect the hearing they have left. Some workers feel that because 

they already have a hearing loss there is no need to protect themselves from loud 

noises anymore. But some hearing is better than none at all. Based on responses from 

the test subjects, a high percentage of workers understand that hearing protection is 

important. Yet, knowing about hearing protection (42) and paying attention to warning 

signs (44) doesn’t always translate into action. However, recognition of ways to protect 

hearing is a good beginning. 

Question J – The correct answers are 45, 46, 47, and 49. Earmuffs and foam earplugs 

that are not worn correctly will offer very little hearing protection or possibly none at all. 

Workers who are not aware of the fact that either type of hearing protection can be used 

incorrectly risk even greater damage to their hearing. Why? Because they will delay 

leaving noisy work areas since they think their hearing is being protected. Of course, 

the latter is true only if their earmuffs and earplugs are being used properly. 

About half of the test subjects chose 45 as a correct answer: 

45. Keep beards or long sideburns trimmed so they don=t affect the seal of earmuffs. 

 [ Correct. Any growth of beard or sideburns will affect the seal and is ] 

 [ discouraged. ] 

This means that about half of the test sample were unaware that long sideburns and full 

beards interfere with the seal of earmuffs. Earmuffs require a good seal around the ear 

in order to be effective. The pads should be flexible and soft and be capable of 

adjusting to a comfortable tension. Workers with long hair need to be especially careful. 

Rolling and squeezing foam ear plugs (46) is the only way to get them thin enough for 

proper placement in the ear canal. Pulling the ear up and back (47) is important 

because this straightens out the ear canal so that the foam plug can be placed in far 

enough to be effective. 

More than 80% of the test subjects incorrectly chose 48 as a correct answer: 

48. After placing the rolled and squeezed ear plug in your ear, release it. It will expand 

to give you a snug fit. 

 [ You need to use your finger to keep it in place in the ear canal while it ] 

 [ swells up. ] 

A rolled and squeezed foam ear plug will not stay in the ear canal after it expands 

unless it is held in place with a finger. Holding the plug in the ear for about 20 seconds 

will allow the plug to expand in place and provide a snug fit. 

Both earmuffs and foam plugs should be worn together for extremely loud noise (49). 

But a worker may be unable to hear any shouts or warnings from other persons. This is 

a safety hazard. The best way to deal with extremely loud noise is with caution and by 

combining plugs and muffs only if absolutely necessary. 

Finally, dirty ear plugs can cause infection. Hands should be clean to reduce that 

possibility. Because foam ear plugs are inexpensive, dirty ones should be thrown away 

and not reused (50). 
Drill Rig Incident 

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Question K – The correct answers are 51, 52, 53, and 54. With good hearing, workers 

will be able to work more safely on the job (51), communicate with other employees, 

and still be able to hear equipment warning signals and instructions from coworkers. 

The ability to hear is also a factor in the total enjoyment of family and friends (52). 

Communicating with others (53) is frustrating and difficult for anyone who has a hearing 

loss. People must understand that once hearing is lost, it is gone forever (54). 

Many people think that hearing aids restore hearing to normal. Hearing aids are simply 

tiny electrical amplifiers that make all sounds louder. They expand the range of sounds 

a person can hear, but do nothing for returning the ability to hear. Surgery to rebuild the 

inner ear and cochlear implants are available, but these are not effective for everyone 

and they are expensive. The best ways to protect hearing are using hearing protection, 

limiting time in noisy work areas in accordance with company and OSHA guidelines, 

and avoiding activities in which exposure is possible. 
Drill Rig Incident 

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Scoring Key 

The correct answers are marked with an asterisk.7

Question Answer Number 

 A 1 2 3 4* 

 B 5 6 7* 8 9 

 C 10 11* 12* 13* 

 D 14 15* 16* 17* 18 

 E 19 20 21 22* 

 F 23* 24 25* 26* 27 28* 29 

 G 30* 31 32* 33* 34* 35* 

 H 36* 37* 38* 

 I 39 40* 41* 42* 43 44* 

 J 45* 46* 47* 48 49* 50 

 K 51* 52* 53* 54* 

 

7

This page is printed in large type so that it may be copied and used as an overhead transparency. 
Drill Rig Incident 

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Summary of Field Test Results 

NIOSH evaluated the Drill Rig Incident exercise to determine its effectiveness for 

teaching workers about noise, hearing loss, and hearing protection. A sample of 

180 persons participated in a field experiment that consisted of two parts. In the first 

part, subjects completed either a pretest before working the DRI exercise or a posttest 

after working the exercise. Important: This was an either/or situation, as no subjects 

completed both a pretest and a posttest. The second part of the experiment consisted 

of all subjects answering questions (called a self-reporting measure) on their opinion of 

the validity and utility of the exercise. 

The experimental procedure used in the first part is called a “split-group” pretest/

posttest assessment. This means that each of the 180 subjects in the sample group 

was placed, by random draw, into either a control group or an experimental group. The 

subjects in the control group took the pretest before working the DRI training exercise, 

and the subjects in the experimental group took the posttest after working the exercise. 

The dependent variable in the experiment was subjects’ score on either the pretest or 

posttest. The pretest and posttest are an identical set of 24 true or false questions 

about the topics included in DRI, namely, noise, hearing loss, and hearing protection. 

If the experimental group’s average score in the posttest would be higher than the 

control group’s average score in the pretest, it would support the belief that subjects in 

the experimental group learned about noise, hearing loss, and hearing protection from 

working the DRI exercise and therefore scored higher in the posttest. Those who took 

the pretest did not have the benefit of working DRI before being tested, so theoretically 

they know less about noise, etc., and therefore should score lower. If posttest scores 

are higher than pretest scores, it can be concluded that DRI is the reason and, as a 

result, it is an effective training exercise. 

In this type of investigation, it is important that the experimental and control groups are 

“equivalent.” Equivalent groups, for research purposes, means that subjects have 

equivalent backgrounds and work-related experience, as well as similar knowledge of 

the training material content, coming into the experiment. It follows that if the research 

groups are equivalent, then improved scores in the posttest will be a direct result of the 

DRI training received and not due to other outside effects. 

It was determined that both groups in this experiment are equivalent. The rationale for 

this is: (1) the groups are statistically large enough so that background knowledge of 

noise and hearing protection should be about the same, regardless of how much 

(or how little) is known, (2) subjects were placed into either group by random draw, and 

(3) their demographics suggest equivalency in terms of age and drilling experience. 
Drill Rig Incident 

17

Demographics of Subjects 

 Control Group Experimental Group 

 (Pretest) (Posttest) 

 n mean SD n mean SD p-value

Age 103 42.0 11.6 71 43.5 10.1 0.37 

Yrs. of exper. 96 13.3 12.1 96 13.3 10.0 0.98 

The t-test was used to examine whether the control group pretest scores were 

significantly different from the experimental group posttest scores. The mean posttest 

score (20.22) was significantly higher than the mean pretest score (18.87), as shown 

below. 

Analysis of Pretest/Posttest Scores Independent Samples t-test 

 Group n Mean SD t-value p-value

 Control 108 18.87 2.24 

 4.11 <0.0001 

 Experimental 72 20.22 2.04 

The second part of the experiment consisted of all subjects indicating their level of 

agreement or disagreement with the statements shown below. This self-reporting 

measure was used to assess the validity and utility of DRI as a training exercise. 

Think about the exercise you just finished. Circle the number that tells how much you agree or 

disagree with the statements below. 

Definitely Definitely 

 Disagree Agree 

1 2 3 4 5 

1. This situation could happen at a drill site. 1 2 3 4 5 

2. The exercise will help me remember 

 something important about noise and 

 hearing loss. 1 2 3 4 5 

3. I learned something new from this exercise. 1 2 3 4 5 

4. The exercise took too long to complete. 1 2 3 4 5 

5. I liked working the exercise. 1 2 3 4 5 

6. I will use some of the ideas presented to 

 protect my hearing. 1 2 3 4 5 

7. The way the material was presented is 

 a good way for me to learn. 1 2 3 4 5 

8. The exercise was easy to read. 1 2 3 4 5 
Drill Rig Incident 

18

The number and percentage of subjects who responded to these statements are shown 

below. 

Statement N Agree, %8 Disagree, % 

1. This situation could happen at a drill site. 179 92.2 0.6 

2. The exercise will help me remember 179 88.2 1.1 

 something important about noise and 

 hearing loss. 

3. I learned something new from this 179 73.3 6.2 

 exercise. 

4. The exercise took too long to complete. 179 4.5 76.5 

5. I liked working the exercise. 179 66.5 8.4 

6. I will use some of the ideas presented to 179 89.4 1.1 

 protect my hearing. 

7. The way the material was presented is a 179 89.9 2.8 

 good way for me to learn. 

8. The exercise was easy to read. 179 91.6 1.7

Statements 1, 2, and 3 report on participants’ assessment of the validity of DRI. As 

shown above, 99.2% indicate that the “situation could happen at a drill site,” 88.2% 

agree that DRI will help them “remember something important” about noise and hearing 

loss, and 73.3% of the subjects indicate they “learned something new” from DRI. 

Finally, 89.4% of the participants indicate they will “use some of the ideas presented to 

protect” their hearing. 

 

8

 “Agree” is the sum of responses 4 and 5. 
Drill Rig Incident 

19

Answer Key for Pretest / Posttest Questions 

Directions: Circle T for True or F for False.

1. It takes years of exposure to loud noise for hearing loss to develop. T F

2. It’s possible to use foam ear plugs incorrectly. T F 

3. It’s possible to use earmuffs incorrectly. T F 

4. Hearing loss is preventable. T F 

5. You can’t hear someone talking when you are wearing foam ear plugs. T F

6. Foam ear plugs are effective only if they are used properly. T F 

7. Because drill rigs are so noisy, hearing loss is bound to happen to 

 workers. T F

8. Our ears eventually adjust to loud noise. T F

9. Persons who talk too loud generally have a hearing loss. T F

10. Constant ringing in your ears may be a sign of hearing loss. T F 

11. To people with a hearing loss, normal conversation can sound like 

 people are mumbling. T F 

12. If you have to shout to be heard around a drill rig, then noise is too loud. T F 

13. If you can’t talk with someone standing 2 feet away while the drill rig 

 is running, then the noise level is too loud. T F 

14. After placing rolled and squeezed foam ear plugs into your ear canal, 

 they expand to give you a snug fit. T F

15. Dirty foam ear plugs should be thrown away and replaced with clean 

 ones. T F 

16. If foam ear plugs are not rolled and squeezed, they can still be inserted 

 properly into your ears. T F

17. Dirty foam ear plugs work as well as clean ones. T F

18. Hearing loss can be reversed. T F

19. Pulling your ear up and back is not always necessary before inserting 

 foam ear plugs. T F

20. Hearing loss is a health problem, not a safety problem. T F

21. Once you have a hearing loss, it is permanent. T F 

22. If you have a hearing loss, time away from a noisy drill rig will allow 

 your hearing to return. T F

23. Wearing a hearing aid will bring your hearing back to normal. T F

24. One way to ensure that workers use hearing protection is to post 

 “Hearing Protection Required” signs at the workplace. T F

The correct answers appear in bold. 
Drill Rig Incident 

Appendix A: Problem Booklet 

Duplicate this copy of the problem booklet for use in your classes. Booklets should be 

printed on only one side of the paper. Each person in your class should have a 

problem booklet while he/she is working the exercise. The problem booklets are 

reusable. 
Drill Rig Incident 

Drill Rig Incident 

Problem Booklet
Drill Rig Incident 

2 

Instructions 

Begin by reading the Background and Problem described on the next page. Then 

answer each of the questions that follow. Do them one at a time in the order they 

appear. Don't jump ahead, but you may look back at earlier questions and answers at 

any time. 

Some questions ask you to select as MANY answers that you think are correct. Other 

questions ask you to select only ONE answer, unless you are told to "Try again." 

Follow the directions for each question. 

After you have selected an answer choice to a question, look for its number on the 

answer sheet. Rub the developing pen between the brackets of your selection on the 

answer sheet. Be sure to fill in all of the space between brackets; a message will 

appear and tell if you are correct. 

When you have finished the questions, follow the instructions to determine your score 

for the exercise. 
Drill Rig Incident 

3 

Background 

You are the drill foreman of a three-person drilling crew. 

The other members of your crew are Billy, your helper, and Willy, an extra laborer. 

You have over 20 years of experience as a driller. 

Billy’s job is to operate the breakout wrench at the rear of the rotary drill rig. 

Billy called in sick this morning. The only person you were able to find to replace him on 

short notice was your cousin Vinny. 

Vinny has 5 years’ experience on a drilling crew, but hasn’t worked on a drill rig for 

some time. 

 

Your company has recently hired a safety manager, Rip, who has several years of 

experience in the drilling industry. 

Today is a cool and foggy day. 

Your company is drilling a 10-inch-diameter replacement water well for the city. They 

are using a 10-inch-diameter air hammer with 41⁄2-inch API rods as the drill string. 

Problem 

Your crew’s assignment is to pick up where the night shift left off. The night shift strung 

10 rod sections plus a dummy casing section in the hole. You are just starting to 

remove the 10-foot rod sections. 

The drill rig is running. As Vinny goes back for a work glove that he dropped, you 

remind him to “be sure to step back after you attach the automatic chuck.” He then 

latches the breakout wrench around the first pipe section above the threaded joint. You 

hesitate so he can step back. Vinny does not step back and the wrench begins to 

spring back. When you realize what is happening, you shout the word “back” to him, 

but he doesn’t move. 
Drill Rig Incident 

4 

Question A 

You see that the pipe is not breaking apart and more pressure is needed. Because of 

the added pressure, you become alarmed since Vinny has not moved out of the way. 

You know that the wire rope holding the wrench can break. What should you do first? 

(Choose only ONE unless you are told to “Try again.”) 

1. Shout again at Vinny to move back. 

2. Get Vinny’s attention by waving your arms for him to move back. 

3. Do nothing and let the wire rope do its job. Vinny will be OK. 

4. Shut down the rig using an emergency stop switch, sometimes called a “kill” 

switch. 
Drill Rig Incident 

5 

Question B 

As you hit the kill switch, the wire rope suddenly snaps. The breakout wrench springs 

back and strikes Vinny in the chest, knocking him down. You move to help him. 

Fortunately, Vinny only got the wind knocked out of him. He is embarrassed and insists 

that you start the drill right away. What should you do? (Choose only ONE unless you 

are told to “Try again.”) 

5. Nothing. Vinny didn’t get hurt. 

6. Try to find out why the wire rope broke. 

7. Report the incident to your company safety manager right away. 

8. Try to find whose fault it is that Vinny got hit by the wrench. 

9. Start the drill and go back to work. 
Drill Rig Incident 

6 

Question C 

You call the safety manager on your cell phone to report the incident. You tell him that 

Vinny seems to be OK and you expect work to continue. Rip said he would stop by the 

drill site around lunchtime today. Your crew continues pulling drill rods from the hole. 

Rip arrives at the job site before noon and begins to talk with each of you about the 

incident. Why is Rip doing this? (Select as MANY as you think are correct.) 

10. He is trying to find someone to blame. 

11. He wants to learn the details of the incident while it is still fresh in your minds. 

12. He is looking for information that can be used in future safety classes. 

13. He is looking for ways to improve safety in drilling 10-inch holes. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

7 

Question D

After spending some time with your crew, Rip identified several factors that he believes 

contributed to the incident. What factors did he identify? (Select as MANY as you think 

are correct.) 

14. Poor visibility/bad weather conditions. 

15. Failure to follow accepted work practices. 

16. Breakdown in communication. 

17. Vinny staying in a dangerous position. 

18. Loud drill rig noise. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

8 

Question E

Three factors were identified that contributed to the incident: failure to follow accepted 

work practices, Vinny staying in a dangerous position, and breakdown in 

communication. All of these will need to be addressed in order to prevent similar 

incidents in the future, but Rip believes that the breakdown in communication was the 

underlying factor that caused the others. He believes it should be addressed first 

because it has the greatest potential for causing other dangerous situations at a drill 

site. What do you think is the most likely reason for this communication breakdown 

between you and Vinny? (Choose only ONE unless you are told to “Try again.”) 

19. Vinny didn’t hear you shouting at him because he was using foam ear plugs. 

20. Vinny wasn’t paying attention. 

21. Vinny figured the wire rope was safe and he didn’t need to move back. 

22. Vinny has a hearing loss. 
Drill Rig Incident 

9 

Question F 

Rip knows that all people who work around drill rigs are exposed to loud noise, and he 

suspects that Vinny may not be the only one to have a hearing loss. For Rip, hearing 

loss is a safety issue as well as a health issue. 

Because others may have a similar hearing loss, Rip believes that a serious injury or 

fatality could happen to anybody. He decides to design a training program to teach his 

employees about noise and hearing. He asks for your thoughts on what basic facts to 

use for building such a program. What would you tell him? (Select as MANY as you 

think are correct.) 

23. Hearing loss is permanent. 

24. Our ears will eventually adjust to loud noise. 

25. Hearing loss is not reversible. 

26. Hearing loss is preventable. 

27. Hearing loss can be cured. 

28. Hearing loss causes stress in people. 

29. Hearing loss develops after many years of exposure to loud noise. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

10 

Question G 

You think that the training program should teach workers how to recognize signs of 

hearing loss. You want to suggest ways that they can judge for themselves if their 

hearing is bad. Which of the following would you recommend that Rip include in the 

training? (Select as MANY as you think are correct.) 

30. They often ask people to repeat what they are saying. 

31. Someone tells them they talk too loud. 

32. They have trouble hearing normal conversation. 

33. They complain about people mumbling. 

34. They have constant ringing or buzzing in their ears. 

35. Others complain that the TV is too loud. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

11 

Question H 

Rip thinks it is important for workers to know when noise levels around them are too 

loud. Without using noise-measuring instruments, there are ways that a person can tell 

if noise is too loud. Which of the following could Rip use to get this point across in his 

training? (Select as MANY as you think are correct.)

36. Noise is too loud if it causes pain in your ears. 

37. Noise is too loud if you can’t hear someone talking from 2 feet away. 

38. If you have to shout to be heard, then the noise is too loud. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

12 

Question I

Next, Rip would like drillers to learn how to deal with loud noise around drill rigs. What 

can Rip tell them to do to protect their hearing? (Select as MANY as you think are 

correct.) 

39. Use more water around the drill hole. 

40. Try to spend shorter periods of time in noisy areas during the shift. 

41. Ask their supervisor to do something to reduce the noise level. 

42. Wear properly fitted hearing protection. 

43. Start up any other equipment located at the drill site in order to drown out the drill 

rig noise. 

44. Comply with all “Hearing Protection Required” warning signs. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

13 

Question J

Hearing protection is a simple way to protect the hearing you have left. Rip is 

concerned that some workers do not know how to use hearing protection properly. 

What should be included in the training program to teach this? (Select as MANY as 

you think are correct.) 

45. Keep beards or long sideburns trimmed so they don’t affect the seal of earmuffs. 

46. Roll and squeeze foam ear plugs before inserting them. 

47. Pull your ear up and back to open up your ear canal before inserting ear plugs. 

48. After placing the rolled and squeezed ear plug in your ear, release it. It will expand 

to give you a snug fit. 

49. Use earmuffs and foam plugs together for extremely loud noise. 

50. If foam ear plugs are dirty, you can still use them. 

When you have made your selection(s), do the next question. 
Drill Rig Incident 

14 

Question K

Hearing gets worse with age. However, hearing loss will happen much sooner to 

drillers who don’t protect their hearing. What benefits are there to protecting the hearing 

you have left? (Select as MANY as you think are correct.) 

51. Work can be done more safely. 

52. Activities with family and friends may be more enjoyable. 

53. Communicating with others will be easier and more rewarding. 

54. Once it is lost, hearing is gone forever. 

End of Problem 

Scoring your performance 

1. Count the total number of responses you colored in that were marked "correct." 

Write this number in the first blank on the answer sheet. 

2. Count the total number of "incorrect" responses you colored in. Subtract this 

number from 21. Write the difference in the second blank on the answer sheet. 

3. Add the numbers on the first and second blanks. This is your score. 

The highest possible score is 54. 

The lowest possible score is 0. 
Drill Rig Incident 

Appendix B: Blank Answer Sheets 

Copies of these blank answer sheets may be duplicated in the normal fashion. 

However, the answers that are found within the brackets must be printed on these blank 

answer sheets in invisible ink. These answers are found in appendix C. If you have the 

capability to print invisible ink, make copies of the blank answer sheets. Make a master 

of the answers that appear in appendix C. Then print the invisible ink on the blank 

answer sheets, making sure that all pages print and that the appropriate answers line 

up with the appropriate blanks. The Master Answer Sheet shows all of the answers in 

their proper places. 

The exercise is designed to be used in small groups. You will need one answer sheet 

for each group of three to five persons in your class. The answer sheets are 

consumable. You will need a new set for each class. 

A special developing pen is needed by the person within each group who marks the 

answer sheet. "PENIB" developing pens may be obtained from SICPA Customer 

Service, 8000 Research Way, Springfield, VA 22153, phone: 1–888–742–7287. 
Drill Rig Incident 

1 

Answer Sheet for Drill Rig Incident

Use this answer sheet to mark your selections. Rub the developing pen gently and 

smoothly between the brackets. Don't scrub the pen or the message may blur. Be sure 

to color in the entire message once you have made a selection. Otherwise, you may not 

get the information you need. The last part of the message will tell you what to do next. 

Question A (Choose only ONE unless you are told to "Try again.") 

1. [ ] 

2. [ ] 

 [ ] 

3. [ ] 

 [ ] 

4. [ ] 

 [ ] 

Question B (Choose only ONE unless you are told to "Try again.") 

5. [ ] 

 [ ] 

6. [ ] 

 [ ] 

7. [ ] 

 [ ] 

 [ ] 

8. [ ] 

9. [ ] 

Question C (Select as MANY as you think are correct.) 

10. [ ] 

11. [ ] 

 [ ] 

12. [ ] 

 [ ] 

13. [ ] 

 [ ] 
Drill Rig Incident 

2 

Question D (Select as MANY as you think are correct.) 

14. [ ] 

 [ ] 

15. [ ] 

 [ ] 

16. [ ] 

17. [ ] 

 [ ] 

18. [ ] 

 [ ] 

Question E (Choose only ONE unless you are told to "Try again.") 

19. [ ] 

 [ ] 

20. [ ] 

 [ ] 

21. [ ] 

 [ ] 

22. [ ] 

 [ ] 

Question F (Select as MANY as you think are correct.) 

23. [ ] 

24. [ ] 

 [ ] 

25. [ ] 

26. [ ] 

 [ ] 

27. [ ] 

 [ ] 

28. [ ] 

 [ ] 

29. [ ] 
Drill Rig Incident 

3 

Question G (Select as MANY as you think are correct.) 

30. [ ] 

 [ ] 

31. [ ] 

 [ ] 

32. [ ] 

33. [ ] 

 [ ] 

34. [ ] 

35. [ ] 

Question H (Select as MANY as you think are correct.) 

36. [ ] 

37. [ ] 

 [ ] 

38. [ ] 

 [ ] 

Question I (Select as MANY as you think are correct.) 

39. [ ] 

40. [ ] 

 [ ] 

41. [ ] 

 [ ] 

42. [ ] 

43. [ ] 

 [ ] 

44. [ ] 

 [ ] 
Drill Rig Incident 

4 

Question J (Select as MANY as you think are correct.) 

45. [ ] 

 [ ] 

46. [ ] 

 [ ] 

47. [ ] 

 [ ] 

48. [ ] 

 [ ] 

49. [ ] 

 [ ] 

50. [ ] 

 [ ] 

 [ ] 

Question K (Select as MANY as you think are correct.) 

51. [ ] 

52. [ ] 

53. [ ] 

54. [ ] 

 [ ] 

Finding your score 

Number of "Correct" answers you colored in = (1)__________ 

21 minus number of incorrect answers you colored in = (2)__________ 

Add (1) and (2) to get your total score = (3)__________ 

Highest possible score = 54 

Lowest possible score = 0 
Drill Rig Incident 

Appendix C: Invisible Ink Answers 

These pages contain the answers that must be printed in the blanks of the answer sheet 

in appendix B. These answers are spaced and sequenced correctly so that they match 

up exactly with the appropriate blanks on the answer sheet. 

Once the answers have been printed in the answer sheet blanks, the developing pen 

reveals the formerly invisible printed message. 

You may obtain preprinted answer sheets or you may prepare your own copies. To 

learn more about these options and to determine how many answer sheets and 

developing pens you will need, see the “Introduction” section at the beginning of this 

Instructor's Copy. 
 1 Drill Rig Incident 

 1 

 This is not the first thing that needs to be done. Try again. 

 This is not the first thing that needs to be done. Besides, you don’t want to 

 cause Vinny to look away from the drill. Try again. 

 You know that wire ropes have been known to snap. You should do 

 something now. Try again. 

 Correct. You need to stop the rig before Vinny gets hurt. Do the next 

 question. 

 There was no apparent injury, but for Vinny’s sake something should be 

 done. Try again. 

 This isn’t important right now. You will probably learn why the rope broke 

 later on. Try again. 

 Correct. For Vinny’s protection in case any medical problems develop later, 

 the safety manager will need to have some record of the incident. Do the 

 next question. 

 Finding someone to blame is not important. Try again. 

 You need to do something else first. Try again. 

 Finding someone to blame isn’t going to help the situation. 

 Correct. Since no one got hurt he wants to learn the details before anyone 

 forgets what happened. 

 Correct. He may be able to prevent similar incidents by developing SOPs 

 and safety or toolbox meetings using this information. 

 Correct. It is often possible to develop safer ways to complete a task by 

 looking at details of previous incidents. 
 2 Drill Rig Incident 

 2 

 Even though the weather was foggy, the distance between you and Vinny 

 was so close that visibility was not a problem. 

 Correct. The usual work practice is for your helper to back away as soon 

 as he puts the wrench on a rod section. 

 Correct. This is an obvious factor that led to the incident. 

 Correct. He stayed there because he didn’t follow your directions to move 

 back. 

 Even though drill rigs are noisy, Vinny should have been able to hear your 

 directions. 

 Vinny would have been able to hear you shouting even if he was wearing foam 

 ear plugs. Try again. 

 Vinny knows the dangers in drilling, so he was probably paying very close 

 attention. Try again. 

 Vinny has enough experience around drill rigs to know that wire ropes can 

 break. Try again. 

 Correct. If Vinny has a hearing loss, this would explain why he didn’t hear your 

 original instructions or your shouting. Do the next question. 

 Correct. Once your hearing is lost, it will never come back. 

 Our ears don’t adjust to loud noise; we just lose our ability to hear normal 

 sounds. 

 Correct. Damage to a person’s hearing cannot be reversed. 

 Correct. There are a number of things a person can do to prevent 

 hearing loss. 

 There is no way to “cure” hearing loss. Hearing aids can help some people, 

 but not everyone can be helped by a hearing aid. 

 Correct. Stress can develop in persons who have lost some of their hearing 

 because communication becomes difficult. 

 Permanent hearing loss can develop very quickly If noise levels are high. 
 3 Drill Rig Incident 

 3 

 Correct. If this happens most of the time, it’s one sign that a person may 

 have a hearing loss. 

 This doesn’t necessarily mean that they have a hearing problem. A loud 

 voice may be normal for some people. 

 Correct. In most cases, this indicates a hearing loss. 

 Correct. With a hearing loss, it is difficult to hear all of the sounds that are 

 spoken. Conversation may sound like people are mumbling. 

 Correct. Called tinnitus, this is a classic symptom of hearing loss. 

 Correct. 

 Correct. Loud noise often causes physical pain in a person’s ears. 

 Correct. Some call this the “2-foot rule,” and it’s a good way for drillers and 

 other workers to realize that noise in their workplace is too loud. 

 Correct. Noise is too loud if you can’t hear someone talking from 2 feet 

 away 

 This will not contribute to noise reduction. 

 Correct. Getting away from drill rig noise for short periods of time will help to 

 reduce their total exposure time during a shift. 

 Correct. It’s possible that some type of control can be used to reduce 

 drill rig noise levels or time of worker exposure to noise. 

 Correct. This is a sure way to protect a person’s hearing. 

 Noise from other equipment just adds to the total noise level and would only 

 make matters worse. 

 Correct. This is a reminder to all workers that noise levels are high and that 

 everyone should be using hearing protection. 
 4 Drill Rig Incident 

 4 

 Correct. Any growth of beard or sideburns will affect the seal and is 

 discouraged. 

 Correct. This makes the ear plugs thinner so they can be inserted into 

 your ear canal. 

 Correct. This will straighten out the ear canal and make it easier to insert 

 the plug. 

 You need to use your finger to keep it in place in the ear canal while it 

 swells up. 

 Correct. Combining both types of hearing protection should be done only for 

 very loud noise. 

 Dirty ear plugs do not give the same protection as clean ones. There is 

 also a danger of infection. Dirty ear plugs should be thrown away and 

 replaced with new ones. 

 Correct. 

 Correct. 

 Correct. 

 Correct. Although hearing aids may help, they can never bring back 

 normal hearing. 
Drill Rig Incident 

Appendix D: Pretest / Posttest Questions 

This page contains the pretest / posttest questions that may be administered to the 

class. Duplicate these for each person in your class. These should be printed on 

only one side of the paper.
Drill Rig Incident 

Pretest / Posttest Questions 

Directions: Circle T for True or F for False.

1. It takes years of exposure to loud noise for hearing loss to develop. T F 

2. It’s possible to use foam ear plugs incorrectly. T F 

3. It’s possible to use earmuffs incorrectly. T F 

4. Hearing loss is preventable. T F 

5. You can’t hear someone talking when you are wearing foam ear plugs. T F 

6. Foam ear plugs are effective only if they are used properly. T F 

7. Because drill rigs are so noisy, hearing loss is bound to happen to 

 workers. T F 

8. Our ears eventually adjust to loud noise. T F 

9. Persons who talk too loud generally have a hearing loss. T F 

10. Constant ringing in your ears may be a sign of hearing loss. T F 

11. To people with a hearing loss, normal conversation can sound like 

 people are mumbling. T F 

12. If you have to shout to be heard around a drill rig, then noise is too loud. T F 

13. If you can’t talk with someone standing 2 feet away while the drill rig 

 is running, then the noise level is too loud. T F 

14. After placing rolled and squeezed foam ear plugs into your ear canal, 

 they expand to give you a snug fit. T F 

15. Dirty foam ear plugs should be thrown away and replaced with clean 

 ones. T F 

16. If foam ear plugs are not rolled and squeezed, they can still be inserted 

 properly into your ears. T F 

17. Dirty foam ear plugs work as well as clean ones. T F 

18. Hearing loss can be reversed. T F 

19. Pulling your ear up and back is not always necessary before inserting 

 foam ear plugs. T F 

20. Hearing loss is a health problem, not a safety problem. T F 

21. Once you have a hearing loss, it is permanent. T F 

22. If you have a hearing loss, time away from a noisy drill rig will allow 

 your hearing to return. T F 

23. Wearing a hearing aid will bring your hearing back to normal. T F 

24. One way to ensure that workers use hearing protection is to post 

 “Hearing Protection Required” signs at the workplace. T F 
Delivering on the Nation’s Promise:

Safety and health at work for all people

Through research and prevention

For information about occupational safety and health topics contact NIOSH at:

1–800–35–NIOSH (1–800–356–4674)

Fax: 513–533–8573

E-mail: pubstaft@cdc.gov

www.cdc.gov/niosh

SAFER • HEALTHIER • PEOPLETM

DHHS (NIOSH) Publication No. 2005–108