We issue respirators. Do we still need air monitoring?

This page explains what the rules and common practice call for. Every site is different, and what a survey or a filing needs at your facility is something we work out with you after we see it.

Almost certainly yes. OSHA's respiratory protection standard is itself one of the reasons why.

This is one of the most common misunderstandings in industrial hygiene. It is also a costly one, because it usually comes to light during an inspection, not before.

What the respiratory protection standard requires

The standard says the employer must identify and evaluate the respiratory hazards in the workplace. That evaluation must include a reasonable estimate of employee exposures, and it must also identify the chemical state and physical form of the contaminant.

Then, in the same paragraph, comes the sentence that does the real work. Where the employer cannot identify or reasonably estimate the exposure, the employer must treat the atmosphere as immediately dangerous to life or health.

Read that consequence carefully. If you cannot estimate the exposure, the standard does not excuse you from the assessment. It places you in the most protective and most expensive category there is, which requires a supplied-air respirator or a self-contained breathing apparatus, with escape provisions, standby personnel and communications. Nobody wants to run a paint booth on those terms.

A note on what this paragraph is and is not. It creates a duty to assess. It does not set how often you must monitor, and there is no sampling schedule anywhere in the respiratory protection standard. It therefore cannot be the source of a "you must sample every year" obligation. What it does is make an exposure estimate mandatory, and make the cost of not having one severe.

Three more reasons PPE does not replace exposure data

1. You cannot select a respirator without a number. Each type of respirator has an assigned protection factor, and these factors are ratios. A half-mask air-purifying respirator has an assigned protection factor of 10, and a full-facepiece powered air-purifying respirator rates a good deal higher. To know whether a factor of 10 is adequate, you need the airborne concentration that the factor is applied to. Without a measured exposure, you have no basis to conclude that any given respirator is adequate.

2. Exposure is judged as if the respirator were not there. Every substance-specific OSHA standard sets its own trigger for exposure monitoring, and none of them has an exemption for personal protective equipment (PPE).

The silica standard puts this in its definitions. Employee exposure means the exposure to airborne silica dust "that would occur if the employee were not using a respirator," the standard says. That definition governs every exposure decision in the standard, including initial monitoring, periodic monitoring and reassessment, not only the comparison with the action level.

So you do not get to subtract the respirator before you decide whether you owe a program. Issuing respirators does not move a worker below the action level. It protects the worker inside a program you are still required to run.

3. Other controls come before PPE, and you cannot evaluate controls you never measured. The substance-specific standards require feasible engineering controls, such as ventilation, and feasible work practice controls, with respirators used while those are put in place. You have to show that you evaluated engineering controls and that they were or were not feasible. To show that, you need to know what the exposure is and where it comes from.

The situation this really describes

Most plants that ask this question are not trying to cut corners. They have a genuinely hazardous operation, they issued good respirators in good faith, and they assumed that was the responsible thing to do.

It was, as far as it went. What is missing is the exposure assessment, which tells you:

• Whether the respirators you selected are the right ones
• Whether the exposure is high enough to require other controls
• Whether you owe a written program, medical evaluations, fit testing and air monitoring on a schedule

Often the assessment comes back with exposures well below the limits. In that case the honest answer is that the respirator program can be scaled back or made voluntary. A voluntary program has its own, much lighter set of requirements under the respiratory protection standard. That is a real outcome, and it saves real money.

Respirator programs and fit testing are outside the four fields we work in. Our part is the air monitoring that gives you the number.

What it takes to find out

It takes a full-shift survey of a representative sample of each similar exposure group (SEG), meaning workers who do the same job the same way. A single substance usually takes one field day.

→ How many air samples you need · → What drives survey cost · → How often OSHA requires monitoring