5.11 PPE, Respiratory Protection & Biological Hazards

PPE, Respiratory Protection & Biological Hazards

The ABC criteria list "inspect plant safety equipment (e.g., PPE, fire extinguishers, atmosphere detectors)," "maintain safety equipment (e.g., gas detectors, eye-washes, safety showers, respirators)," and "train staff/contractors on safety requirements of the facility and safe work practices." Personal protection is the last line of defense in the hierarchy of controls, and it is the one an operator personally depends on.

---

1. The Hazard Assessment Comes First

OSHA's general PPE standard (29 CFR 1910.132) requires the employer to:

1. Assess the workplace for hazards requiring PPE;
2. Certify that assessment in writing, identifying the workplace, the person certifying, and the date;
3. Select and require appropriate PPE;
4. Train each employee on when PPE is necessary, what to use, how to don, doff, adjust and wear it, its limitations, and its care; and
5. Provide most PPE at no cost to the employee. The notable exceptions are non-specialty safety-toe footwear and non-specialty prescription safety eyewear that the employee may take off-site.

PPE is the bottom of the hierarchy of controls - elimination, substitution, engineering controls, administrative controls, then PPE. A plant that answers every hazard with a respirator has skipped four better answers.

---

2. Selecting PPE

---

3. Respiratory Protection (29 CFR 1910.134)

Respirators are used when engineering controls cannot reduce exposure below the permissible limit, during the interim while controls are installed, and in emergencies.

The program requirements

A written program administered by a trained program administrator, covering:

• Selection based on the hazard and its concentration;
• Medical evaluation - a questionnaire or examination by a physician or other licensed health care professional, completed before fit testing or use;
• Fit testing - before initial use, whenever a different facepiece is used, and at least annually, by either a qualitative method (saccharin, Bitrex, isoamyl acetate, irritant smoke) or a quantitative method;
• Training - annually and whenever needed;
• Cleaning, storage, inspection, and maintenance;
• Air quality for supplied-air systems (Grade D breathing air); and
• Program evaluation.

The hard rules

• A tight-fitting facepiece may not be worn with facial hair that comes between the sealing surface and the face, or with anything else that interferes with the seal - including some eyeglass temples, which is why spectacle kits exist for full facepieces.
• A user seal check (positive and negative pressure) is performed every time the respirator is donned. It does not substitute for fit testing.
• Voluntary use of a filtering facepiece still requires the employer to provide Appendix D information.

Assigned protection factors

The APF is the factor by which the respirator reduces the ambient concentration. A half-mask APR with an APF of 10 used where the concentration is 50 times the PEL is inadequate by a factor of five.

The absolute prohibition

An air-purifying respirator may NEVER be used in an oxygen-deficient atmosphere (below 19.5 percent) or in an atmosphere that is immediately dangerous to life or health. A cartridge filters contaminants; it does not make oxygen.

IDLH atmospheres require a pressure-demand SCBA or a pressure-demand supplied-air respirator with an auxiliary escape SCBA - plus the standby, communication, and rescue requirements of 1910.134(g).

Cartridge and canister selection must match the contaminant, and end-of-service-life indicators or a change schedule are required for gases and vapors. There is no approved air-purifying cartridge for carbon monoxide in ordinary service, and organic vapor cartridges have no reliable warning properties for many chemicals.

---

4. Atmospheric Hazards Specific to This Work

Gas detector maintenance is a recurring operator duty: bump test before each day's use with a known gas, calibrate on the manufacturer's schedule (commonly monthly to quarterly), replace sensors at end of life, and check the pump and sample tubing on remote-sampling instruments. A four-gas meter that has not been bump tested is an unverified assumption, not a safety device.

---

5. Biological Hazards

Raw wastewater and biosolids contain the full spectrum of enteric pathogens: bacteria (Salmonella, Shigella, Campylobacter, pathogenic E. coli, Leptospira), viruses (hepatitis A, norovirus, enterovirus), protozoa (Giardia, Cryptosporidium, Entamoeba), and helminths (Ascaris ova).

Exposure routes

• Ingestion - hand to mouth, the dominant route. Aerosols swallowed after deposition in the throat.
• Inhalation of aerosols - generated by aeration, screening, dewatering centrifuges, and pressure washing.
• Contact with broken skin - any cut or abrasion is an entry point; Leptospira enters through mucous membranes and abraded skin.
• Needlesticks and sharps in screenings and grit - a real and underappreciated hazard at headworks.

Controls

1. Hand hygiene - wash before eating, drinking, smoking, or using the restroom, and at the end of the shift. This single practice does more than all others combined.
2. No eating, drinking, or smoking in process areas, and separate break areas.
3. Separate work clothing from street clothing; provide laundering; do not take contaminated clothing home. Provide lockers with separated clean and dirty sides.
4. Cover all cuts and abrasions with waterproof dressings before the shift.
5. PPE - gloves, eye protection, and where aerosols are generated, respiratory protection.
6. Avoid high-pressure washing where it creates aerosols; use lower pressure or wet methods.
7. Sharps handling - never reach into screenings by hand; use tongs and puncture-resistant containers.

Immunizations

Recommended practice for wastewater and collection system workers:

• Tetanus and diphtheria (Td/Tdap) - current, with a booster every 10 years. Universally recommended.
• Hepatitis B - required to be offered at no cost to employees with occupational exposure to blood or other potentially infectious materials under the Bloodborne Pathogens Standard (29 CFR 1910.1030); commonly offered to wastewater staff.
• Hepatitis A - commonly recommended for wastewater workers.
• Polio, typhoid, and MMR status reviewed by occupational health as appropriate.

The Bloodborne Pathogens Standard

It applies wherever employees have reasonably anticipated occupational exposure to blood or other potentially infectious materials - which at a utility usually means designated first-aid responders rather than all operators. Where it applies, it requires an exposure control plan reviewed annually, universal precautions, engineering and work practice controls, PPE, hepatitis B vaccination offered within 10 working days of assignment, post-exposure evaluation and follow-up, labels and signs, training, and a sharps injury log.

---

6. Heat and Cold Stress

Heat. Virginia summers put operators in confined spaces, on dark rooftops, in trenches, and in chemical suits.

• Heat exhaustion - heavy sweating, cool clammy skin, weakness, nausea, headache, fast weak pulse. Move to a cool place, loosen clothing, provide fluids, cool actively.
• Heat stroke - a medical emergency. Hot skin (which may be dry or wet), core temperature typically above 104 degrees F, confusion, slurred speech, seizure, loss of consciousness. Call 911, cool aggressively and immediately with ice water immersion if available.
• Controls: water, rest, shade, acclimatization over 7 to 14 days for new or returning workers, work/rest cycles, and a buddy system. Impermeable chemical suits eliminate evaporative cooling entirely and dramatically shorten safe work time.

Cold. Winter work on mains and lift stations.

• Hypothermia - shivering (which stops as it worsens), confusion, slurred speech, loss of coordination.
• Frostbite - numbness, waxy white or grayish skin, firm to the touch. Do not rub; rewarm gradually.
• Controls: layered clothing, dry clothing (wet clothing is the leading contributor), warm break areas, and awareness that cold hands make every other task less safe.