The Occupational Safety Leadership Podcast

Episode 45 - Employee Participation in Process Safety Management (PSM)

In today's episode, Dr. Ayers discusses employee participation in Process Safety Management (PSM) and why it might be the most important section of the OSHA PSM Standard.

Episode 44 - Common Process Safety Management Chemicals

In today's episode, Dr. Ayers discusses the common Process Safety Management Chemicals and goes over some examples.  Additionally, common flammable gases and flammable liquids exceeding 10,000 pounds are covered.

Episode 43 - Introduction to Process Safety Management (PSM)

In today's episode, Dr. Ayers discusses Process Safety Management (PSM).  In this introductory podcast on PSM, the 14 elements are briefly discussed along with who's in PSM and who is exempt.

Episode 42 - Shawn Galloway - Proact Safety

In today's Episode, guest Shawn Galloway and I discuss complacency in occupational safety along with coaching employees.  Shawn shares a lot of lessons learned along with the importance of storytelling.

Episode 41 - Parts per Million (PPM) in an air sample

In today's episode, Dr. Ayers discusses how to calculate Parts Per Million (PPM) in an air sample when only given the results in micrograms(ug) and a sample volume of 1.5 m3.  The formulas and the setting up an automated system is discussed.

Episode 40 - Converting Parts Per Million (PPM) to mg-M3 in an air sample

Episode 40 focuses on the reverse conversion of what was covered in Episode 39. Dr. Ayers explains how to convert PPM (a volume‑based concentration) into mg/m³ (a mass‑per‑volume concentration) for air sampling and exposure assessment.

This conversion is essential when comparing monitoring results to OSHA or ACGIH exposure limits, which may be listed in different units depending on the chemical.

 

🔍 Key Concepts Covered

1. Why PPM and mg/m³ Are Not Interchangeable

• PPM = parts of contaminant per million parts of air (volume/volume)

• mg/m³ = milligrams of contaminant per cubic meter of air (mass/volume) Because gases behave differently depending on molecular weight and temperature, a direct conversion requires a formula.

 

2. The Standard Conversion Formula

Dr. Ayers walks through the widely used industrial hygiene equation:

mg/m3=PPM⋅Molecular Weight24.45\text{mg/m}^3 = \frac{\text{PPM} \cdot \text{Molecular Weight}}{24.45}

Where:

• Molecular Weight = chemical’s molecular mass

• 24.45 = molar volume of air at 25°C and 1 atm (standard conditions)

This formula allows you to convert any PPM value into mg/m³ for regulatory comparison.

 

3. When You Need This Conversion

• Lab results reported in PPM, but exposure limits listed in mg/m³

• Comparing results across different sampling methods

• Preparing reports for supervisors or regulators

• Ensuring consistency in exposure assessments

 

4. Automating the Process

The episode also discusses:

• Setting up a spreadsheet or automated calculator

• Pre‑loading molecular weights

• Reducing calculation errors

• Making conversions repeatable and audit‑ready

This mirrors the approach in Episode 39 but in the opposite direction.

 

⭐ Practical Takeaways for Safety Leaders

• Always check the unit of the exposure limit before comparing results.

• Know the molecular weight of the chemical you’re evaluating.

• Use the 24.45 constant for standard conditions.

• Automate conversions to avoid mistakes and speed up reporting.

Episode 39 - Converting mg-M3 to Parts Per Million (PPM)

In this episode, Dr. Ayers explains how to convert airborne contaminant concentrations measured in mg/m³ into parts per million (PPM)—a calculation safety professionals often need when comparing sampling results to OSHA or ACGIH exposure limits.

The episode focuses on understanding the conversion formula, when to use it, and how to automate the calculation for consistent, error‑free reporting.

 

🔍 Key Concepts Covered

1. Why mg/m³ and PPM Are Different

• mg/m³ measures mass per volume

• PPM measures volume per volume Because gases expand and contract with temperature and molecular weight, you can’t convert between them without adjusting for chemistry and conditions.

 

2. The Core Conversion Formula

Dr. Ayers walks through the standard industrial hygiene formula:

PPM=mg/m3⋅24.45Molecular Weight\text{PPM} = \frac{\text{mg/m}^3 \cdot 24.45}{\text{Molecular Weight}}

Where:

• 24.45 is the molar volume of air at 25°C and 1 atm

• Molecular Weight is specific to the chemical sampled

This formula allows you to convert any mg/m³ result into PPM for comparison with exposure limits.

 

3. When You Must Convert

• Comparing mg/m³ sampling results to PPM‑based OSHA PELs

• Aligning lab results with ACGIH TLVs

• Standardizing data across different sampling methods

• Communicating results to supervisors and employees in a familiar unit

 

4. Automating the Calculation

Dr. Ayers discusses:

• Setting up a spreadsheet or automated system

• Pre‑loading molecular weights

• Reducing transcription errors

• Making conversions repeatable and audit‑ready

This is especially useful for safety teams handling multiple chemicals.

 

⭐ Practical Takeaways for Safety Leaders

• Always check whether the exposure limit is in PPM or mg/m³—they are not interchangeable.

• Know the molecular weight of the chemical you’re evaluating.

• Use the 24.45 constant for standard conditions unless you have reason to adjust.

• Automate conversions to reduce mistakes and speed up reporting.

Episode 38 - Negative Attributes of a Safety Audit

In today's episode, Dr. Ayers discusses five negative attributes of safety audits.