| Course | PU635 Survey of Environmental and Occupational Health |
|---|---|
| Unit | Unit 4 |
| Paper type | Control hierarchy application |
| Length | About 1,040 words, 6 pages double-spaced |
| Format | APA 7 student paper |
| School | Purdue University Global |
| Program | Master of Public Health (MPH) |
| Updated | October 2026 |
Free sample paper for PU635 Unit 4
Fourteen Candidates, Three Sources, Five Levels: A Unit 4 Control Hierarchy Application Taking Every Flour Dust Source at a Composite Bakery Down From Elimination Before Anyone Mentions a Respirator
[Student Name]
Purdue University Global
PU635: Survey of Environmental and Occupational Health
Unit 4 Control Hierarchy Application
[Instructor Name]
[Date]
Corliss Street Bakery, its costs and its suppliers are composite; the hierarchy, the control types and the research cited are real.
The Three Sources Carried From Unit 3
1. Sack tipping in the ingredient room: two workers, the highest peaks, and the enzyme in the improver.
2. Dusting flour on the divider and bun line: nine workers, steady exposure across the shift.
3. Compressed-air cleaning: the mixing crew at changeover and the 22 night sanitation workers for hours each night.
The Matrix, Source by Source
Each entry gives the level, the candidate, the verdict, the installed cost and the owner. Source one, sack tipping.
1. Elimination: bulk rye delivered by tanker to a second silo, ending sack tipping for rye. Feasible on the next capital cycle, not now. About 310,000 dollars with a sifter line. Owner: plant manager.
2. Substitution: dough improver bought as granulate rather than powder, which releases far less dust when tipped. Feasible now; the supplier has confirmed by letter that the granulated product has the same enzyme activity. No added cost. Owner: purchasing.
3. Engineering: a bag-dump station with an integral exhaust hood and a sack compactor, so the bag is emptied inside a ventilated enclosure and the empty sack is never shaken. Feasible now. 38,500 dollars installed. Owner: maintenance, with monthly airflow checks.
4. Administrative: slow-start mixing for the first thirty seconds, so dry ingredients are wetted before the bowl reaches speed. Feasible now. No cost. Owner: mixing lead.
5. Protective equipment: half-face respirators with particulate filters for sack tipping until the dump station runs, under a written program. Interim only.
Source two, dusting flour.
6. Elimination: none for the rye line, where dusting is part of the product's surface. Recorded as no candidate, with the reason.
7. Substitution: divider oil instead of dusting flour on the bun line. Feasible after a two-week quality trial on bun shape and release. Under 2,000 dollars a year in oil. Owner: production manager.
8. Engineering: a flour duster that meters a thin layer from a sieve close to the belt rather than a worker shaking a scoop above it. Feasible. 6,200 dollars per line, two lines. Owner: maintenance.
9. Administrative: no hand dusting from above shoulder height, written into the line instructions. Feasible now. Owner: make-up lead.
10. Protective equipment: not recommended for a steady, nine-person, full-shift exposure. The matrix states why: a respirator worn for eight hours by nine people is the control most likely to be removed.
Source three, compressed air.
11. Elimination: compressed air banned on product surfaces, floors and guards, with the hoses removed from the production area rather than merely discouraged. Feasible now. No cost. Owner: plant manager.
12. Substitution: HEPA-filtered industrial vacuums for every line and the sanitation crew. Feasible. Four units at 3,900 dollars each, 15,600 dollars. Owner: sanitation lead and the agency lead jointly.
13. Engineering: a central vacuum system plumbed to each line. Not now. About 120,000 dollars, reconsidered with the silo project.
14. Administrative: wet wiping for ledges and overhead surfaces, scheduled weekly, since settled dust on beams is also a combustible dust concern noted in the walkthrough. Feasible now. Owner: sanitation lead.
Compressed air sits at the top of the hierarchy because removing it eliminates the source, which is the rare case where the cheapest control is also the strongest.
Feasibility Notes
Cost is only one of four tests applied to each candidate. Downtime matters: the dump station needs a two-day installation, scheduled over a holiday weekend. Product quality matters: divider oil changes the crust on buns and has to pass a trial. Maintenance matters most for engineering controls, because an exhaust hood with a clogged filter looks exactly like one that works. The station therefore comes with an airflow gauge and a monthly reading logged by maintenance.
Why Education Alone Is Not on This List
A sector-wide Dutch program that relied mainly on risk education and good work practices produced only modest reductions in bakery exposure, around 2 percent a year for flour dust, though use of local exhaust rose and compressed air fell (Meijster et al., 2009). A randomized intervention study in supermarket bakeries that combined engineering, work practice and training measures reported mean flour dust and allergen exposure falling by half (Baatjies et al., 2014). Training appears in this plan in Unit 9, attached to a specific change in equipment, rather than as a control in its own right.
Respirators as an Interim, and Only as an Interim
Respirators appear once, for the two sack tippers, for the weeks between today and a working dump station. Using them triggers the respiratory protection standard: a written program, medical evaluation, fit testing and training. The interim is dated, and it ends the day the station passes its first airflow check.
Recommendation Set, in Sequence
1. Week 1: remove compressed-air hoses from production, issue HEPA vacuums, and start slow-start mixing and the no-high-dusting rule.
2. Week 2: switch to granulated improver; begin the respirator program for sack tipping.
3. Weeks 3 and 4: run the divider oil trial on the bun line.
4. Month 2: install the bag-dump station and sack compactor, and end the respirator interim.
5. Month 3: fit metered dusters on both make-up lines.
6. Next capital cycle: price the rye silo and the central vacuum together.
What the Set Expects to Change
If the controls work as planned, the highest peaks, from tipping and compressed air, should fall the most, and the steady haze on the make-up line should fall less. The repeat sampling in month 4 uses the same inhalable samplers and task-based method as Unit 3, so the comparison is like for like. Exposure-response work in bakers puts the point where sensitization risk becomes negligible at about half a milligram of inhalable flour dust in each cubic meter of air averaged over a shift, and that is the target the repeat sampling is judged against (Houba et al., 1998).
References
Baatjies, R., Meijster, T., Heederik, D., Sander, I., & Jeebhay, M. F. (2014). Effectiveness of interventions to reduce flour dust exposures in supermarket bakeries in South Africa. Occupational and Environmental Medicine, 71(12), 811-818. https://doi.org/10.1136/oemed-2013-101971
Houba, R., Heederik, D., & Doekes, G. (1998). Wheat sensitization and work-related symptoms in the baking industry are preventable: An epidemiologic study. American Journal of Respiratory and Critical Care Medicine, 158(5), 1499-1503. https://doi.org/10.1164/ajrccm.158.5.9803055
Meijster, T., Tielemans, E., & Heederik, D. (2009). Effect of an intervention aimed at reducing the risk of allergic respiratory disease in bakers: Change in flour dust and fungal alpha-amylase levels. Occupational and Environmental Medicine, 66(8), 543-549. https://doi.org/10.1136/oem.2008.042564
Reading the PU 635 Unit 4 instructions
In Unit 4, the usual task is to apply the hierarchy of controls to the priority hazard from your exposure analysis. Work each source separately and consider every level in order: elimination, substitution, engineering, administrative and personal protective equipment. Name specific candidates rather than categories, and when a level offers nothing, say so with a reason. Judge feasibility on cost, downtime, effect on the product or service, and maintenance. Assign each chosen control an owner who will keep it working. Explain where respirators or other protective equipment fit, including the program requirements they trigger. Finish with a recommendation set in sequence, with dates, and say how you will know whether the controls reduced exposure, ideally with repeat sampling using the same method as before.
How this PU635 Unit 4 example is built
The paper restates the three sources from Unit 3 with the workers each affects. The matrix then runs source by source, numbering fourteen candidates with level, verdict, cost and owner, including a no-candidate entry for eliminating dusting on rye and a rejected central vacuum. A highlighted line explains why the compressed-air ban sits at elimination. Feasibility notes cover downtime, product quality and the airflow gauge that keeps the dump station honest. A short section contrasts a Dutch education-led program's modest reductions with a randomized supermarket bakery trial where combined measures cut flour dust by half, explaining why training is held for Unit 9. Respirators are confined to a dated interim. Six sequenced steps and a note on repeat sampling close the set.
Where the points sit in the PU635 Unit 4 rubric
PU 635 graders typically award most of the points for correct use of the hierarchy: every level considered for each source, in order, with reasons for any level skipped. Specific, realistic candidates earn more than generic categories. Feasibility analysis that weighs cost, downtime, quality and upkeep receives substantial credit, as does assigning responsibility for each control. Instructors look for protective equipment to be treated as a last resort, with the program requirements it brings acknowledged. Evidence that controls work, drawn from intervention studies, strengthens the content score. A sequenced, dated plan with a way to verify results earns the final share, along with APA citations. Submissions that jump straight to masks or training usually lose marks.
PU635 Unit 4 help from the desk
A frequent error is listing controls by convenience rather than by level, which hides the fact that elimination and substitution were never considered. Another is treating training as a control in its own right without tying it to a change in equipment or process. Students often skip feasibility or reduce it to cost, missing downtime and maintenance. Do not recommend respirators for a whole crew on a full shift without addressing the program they require and how often they will actually be worn. Give each control an owner. Keep rejected candidates on the page with reasons, because graders want to see the reasoning. Share your hazard and its sources, and we will prepare a full control matrix with costs, owners and a dated sequence.
Get a PU635 Unit 4 example written to your instructions
List the hazards the PU635 Unit 4 prompt asks about, with whatever is already in place at the workplace, then add the instructions and rubric. The free first custom sample runs each hazard through all five levels, keeps rejected controls with their reasons, names who would maintain what is chosen, and comes back in 24-48 hours. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
More PU635 papers and MPH samples
- PU635 Unit 1: Discussion Board Post
- PU635 Unit 2: Hazard Identification Walkthrough
- PU635 Unit 3: Exposure Route Analysis
- PU635 Unit 5: Chemical Hazard Case Study
- PU635 Unit 6: Seminar Reflection
- PU635 Unit 7: Ergonomic Assessment
- PU635 Unit 8: Regulatory Compliance Analysis
- PU635 Unit 9: Worker Training Material
- PU635 Unit 10: Safety Program Document
- PU615 Unit 4: Goals and Objectives
- PU605 Unit 4: Program Logic Model
- PU580 Unit 4: Dose-Response Analysis
- PU501 Unit 4: County Health Department Profile
PU635 Unit 4 questions, answered
Does every hazard need a control at every level?
No, but every level should be considered. Some levels offer nothing for a given hazard, and saying so with a reason is part of the answer. What graders penalize is a level silently skipped, because it suggests the writer never asked whether elimination or substitution was possible before moving on to engineering or equipment.
What counts as an engineering control versus an administrative one?
An engineering control changes the workplace or equipment so the hazard is reduced without anyone having to remember to do something, such as local exhaust or an enclosure. An administrative control changes how people work, through schedules, procedures or training. The distinction matters because engineering controls keep working when attention lapses, while administrative ones depend on it.
How do I judge feasibility without cost data?
Estimate in ranges and say where the estimate came from, such as a vendor website, a published case or a comparable facility. Feasibility also covers downtime, effects on the product or service, space, and who would maintain the control. A rejection resting on a stated reason, even a rough one, earns more than a rejection with none.
Where can I find a free PU635 Unit 4 sample paper?
The full Unit 4 control matrix, all fourteen candidates with costs and owners, is on this page along with the sequenced recommendations.
Is banning compressed air really elimination?
For the cleaning source it is, because it removes the task that lifts settled dust into the air. Vacuums then replace it, which is substitution.