Objective data: when you can skip exposure 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.

This page explains when you do not need to hire us.

Several of OSHA's substance-specific standards give you a legitimate way to complete your exposure assessment without taking a single air sample, by relying on objective data that shows what the exposure is. If your operation fits one of these standards, buying an air monitoring survey means buying something you already have.

Two standards look as though they offer the same path, but they do not. One offers a narrower version, and the other offers nothing at all.

What counts as objective data

Objective data is information that shows how much of a substance workers are exposed to from a particular product, material, process, operation or activity. It can come from:

• Industry-wide surveys
• Published studies
• Calculations based on the composition of the material
• Air monitoring done at another workplace

One condition applies everywhere this option appears: the data must reflect workplace conditions that closely resemble yours. That means the same material, the same process, the same controls and the same duration. A study of dry cutting does not cover a wet-cutting operation. A supplier's data sheet may show exposures on their equipment, but it does not cover yours if your ventilation differs.

Objective data is not a loophole but a documentation requirement that happens to cost less than sampling. You still have to hold the data, be able to produce it, and be able to explain why it matches your conditions.

Standards with a true objective data or performance option

A performance option means the standard specifies the outcome you must achieve and leaves the method to you.

The action level named in the table is set below the permissible exposure limit.

Silica, hexavalent chromium and beryllium are the strongest cases. Each treats the exposure assessment as an outcome you must achieve, which is to characterize the exposure accurately, and leaves the method to you.

Formaldehyde is in a class of its own, and it is worth reading closely. Its standard does not substitute data for initial monitoring but provides an exemption from measuring at all. Where the objective data supports it, the standard says the employer will not be required to measure worker exposure. It stops there and does not add "for initial monitoring." Methylene chloride and asbestos are the narrower kind, because their standards replace initial monitoring only.

Suppose you run a wet-cutting masonry operation backed by published data that matches it well, or a plating line whose bath chemistry and ventilation match a case that is already documented. In either case this is a sound, defensible way to complete the exposure assessment. You will still want the documentation assembled properly, but you will not need pumps.

→ Hexavalent chromium air sampling · → Cadmium air sampling

Cadmium: initial monitoring only

Cadmium has an objective data option, but a tightly limited one that is worth setting apart from the performance options above.

The cadmium standard lets you rely on earlier air monitoring and on objective data, but both apply to initial monitoring only. They can stand in for the initial determination of what the exposure is, and nothing more.

The provision on periodic monitoring has no matching option, so once you are in the periodic monitoring cycle the standard expects measurement.

The limitation comes from what the standard covers, not from a stated prohibition. The standard does not say "objective data may not be used for periodic monitoring." It simply never grants that option in the provision on periodic monitoring, and a permission the standard does not grant is not yours to use.

Lead: no objective data option at all

Lead is the sharpest case.

OSHA's lead standard has no objective data option. The concept does not appear in the standard's exposure monitoring section.

What lead has is historical sampling data with a hard cutoff. Two provisions of the standard let you rely on measurements of airborne lead taken in the previous 12 months. These must be actual measurements, made at your workplace, within a year. If the data is 13 months old, the standard does not reach it, however well it matches your conditions.

As with cadmium, both provisions deal with the initial determination and initial monitoring, and periodic monitoring gets no substitute.

So you cannot use objective data to complete a lead exposure assessment. Published data, supplier data and studies of similar operations carry no weight under the lead standard. What the standard accepts is measurement, taken at your workplace within the last 12 months.

→ Lead exposure monitoring

A four-question test

Before you pay for sampling, ask:

1. Does the standard for my substance actually contain an objective data or performance option? Six do: silica, hexavalent chromium, beryllium, formaldehyde, methylene chloride and asbestos. Cadmium does, for initial monitoring only, and lead does not at all. Check the standard itself rather than assuming from this list, because these options are scattered and each standard words them differently.
2. Do I have data that truly matches my conditions? That means material, process, controls and duration, and data that only mentions my industry is not enough.
3. Am I within any time limit the standard sets? Lead's 12 months is the strict one.
4. Is this the initial assessment or ongoing periodic monitoring? The answer is often different for the two. See how often OSHA requires monitoring, by substance.

If you pass all four, you have your exposure assessment. Keep the file where you can find it, and review it whenever the process, material or controls change. A change generally reopens the assessment, whichever path you used.

→ How long to keep exposure records and who has access to them

Where objective data stops working

Objective data describes a process, so it cannot tell you that a particular control has deteriorated, that a damper closed or that a new operator works closer to the plume. It has no way to detect gradual change over time.

It is also a weak record in a dispute. Measuring your people on your equipment is a different quality of evidence from pointing to a published study. If you may be heading into a lawsuit, an insurance dispute or an enforcement case, that difference tends to matter more than the cost of the pumps.

→ Similar exposure groups · → Air monitoring surveys