6.1 Occupational Health & Workplace Safety

Occupational Safety and Health Administration (OSHA) Standards

The Occupational Safety and Health Administration (OSHA) was established by the OSH Act of 1970 to ensure safe and healthful working conditions for workers by setting and enforcing standards and by providing training, outreach, education, and assistance. The General Duty Clause, Section 5(a)(1) of the OSH Act, requires employers to provide a workplace free from recognized hazards that are causing or are likely to cause death or serious physical harm.

Hazard Communication Standard (HAZCOM)

The Hazard Communication Standard (HCS), often referred to as "Right-to-Know," requires employers to disclose toxic and hazardous substances in the workplace. OSHA aligned the HCS with the Globally Harmonized System of Classification and Labeling of Chemicals (GHS) to provide a standardized approach to hazard communication.

Safety Data Sheets (SDS): Formerly known as Material Safety Data Sheets (MSDS), SDSs must accompany all hazardous chemicals. They contain 16 standardized sections, including identification, hazard identification, composition, first-aid measures, fire-fighting measures, accidental release measures, handling and storage, exposure controls/personal protection, and toxicological information.

GHS Labeling: Labels on chemical containers must include standardized elements:

• Pictograms: Diamond-shaped symbols with red borders (e.g., flame for flammables, skull and crossbones for acute toxicity).
• Signal Words: "Danger" for severe hazards and "Warning" for less severe hazards.
• Hazard Statements: Describe the nature and degree of the hazard.
• Precautionary Statements: Recommend measures to minimize or prevent adverse effects.

Chemical Hazards and Exposure Limits

Industrial hygienists and environmental health specialists evaluate chemical exposures using various occupational exposure limits.

Types of Exposure Limits

Evaluating TWA requires considering both the concentration of the contaminant and the duration of exposure. If an employee is exposed to different concentrations during the day, the TWA is calculated as: (C1*T1 + C2*T2 + ... + Cn*Tn) / 8.

Physical Hazards

Physical hazards include noise, temperature extremes, radiation, and ergonomic risks.

Noise Exposure Limits

Prolonged exposure to high noise levels causes noise-induced hearing loss (NIHL).

• OSHA PEL: The PEL for noise is 90 dBA for an 8-hour TWA. If noise levels exceed this, engineering or administrative controls must be implemented.
• Action Level: OSHA has established an Action Level of 85 dBA for an 8-hour TWA. When noise reaches or exceeds this level, the employer must implement a comprehensive Hearing Conservation Program (HCP).
• Exchange Rate: OSHA uses a 5 dB exchange rate, meaning that for every 5 dBA increase in noise level, the permissible exposure time is cut in half (e.g., 90 dBA for 8 hours, 95 dBA for 4 hours, 100 dBA for 2 hours).

Temperature Extremes

Heat Stress: Working in hot environments can lead to heat exhaustion or heat stroke. Environmental health professionals use the Wet Bulb Globe Temperature (WBGT) index, which considers air temperature, humidity, radiant heat, and wind speed. Preventive measures include acclimatization, hydration, and implementing work-rest cycles.

Cold Stress: Exposure to extreme cold can result in frostbite or hypothermia. Mitigation involves proper layered clothing, warming shelters, and monitoring wind chill factors.

Ergonomics

Ergonomic hazards occur when there is a mismatch between the physical requirements of the job and the physical capacity of the worker. Risk factors include repetitive motion, awkward postures, high force, and contact stress. Interventions follow the hierarchy of controls, focusing first on redesigning workstations and using mechanical assists (like the NIOSH lifting equation guidelines), and then on rotating job tasks.

Personal Protective Equipment (PPE)

When engineering and administrative controls are insufficient to eliminate hazards, Personal Protective Equipment (PPE) must be used. Employers are required to conduct a hazard assessment to determine the necessary PPE.

• Respiratory Protection: Requires medical evaluation, fit testing, and training. Respirators must be NIOSH-approved.
• Hearing Protection: Earplugs and earmuffs evaluated by their Noise Reduction Rating (NRR).
• Chemical Protection: Gloves, aprons, and suits selected based on chemical compatibility and breakthrough time.

Confined Space Entry Requirements

A confined space is defined by three criteria: it is large enough for a worker to enter and perform work, has limited or restricted means for entry or exit, and is not designed for continuous employee occupancy.

Permit-Required Confined Spaces

A permit-required confined space (PRCS) contains or has the potential to contain a hazardous atmosphere, contains a material that has the potential for engulfing an entrant, has an internal configuration that could trap or asphyxiate an entrant, or contains any other recognized serious safety or health hazard.

Entry Requirements:

1. Atmospheric Monitoring: Before entry, the atmosphere must be tested in this specific order:
   • Oxygen Content: Must be between 19.5% and 23.5%. Levels below 19.5% are oxygen-deficient (asphyxiation risk), and levels above 23.5% are oxygen-enriched (fire/explosion risk).
   • Flammable Gases/Vapors: Must be below 10% of the Lower Explosive Limit (LEL).
   • Toxic Air Contaminants: Must be below the PEL (e.g., carbon monoxide, hydrogen sulfide).
2. Ventilation: Continuous forced-air ventilation is often required to maintain a safe atmosphere.
3. Attendant: A trained attendant must remain outside the space to monitor entrants and initiate rescue if needed.
4. Permit System: A written entry permit must document the hazard evaluation, control measures, and authorized personnel.