Monitoring

Introduction

Monitoring is the measurement of hazardous exposures to physical or chemical agents during a given time period.

During the preliminary workplace survey, the substances or conditions to which workers are exposed must be determined. The basic problem in exposure assessment is to recognize all physical and chemical exposures, to evaluate each as acceptable or unacceptable, and to control all unacceptable exposures.

Hazardous exposures can take various forms and include:

• Chemicals (examples include lead, solvent, pesticides)
• Sound
• Heat/Cold
• Dust (examples include asbestos, cotton, silica)
• Radiation
• Biological agents (examples include fungus, bacteria, virus)

Once an exposure has been determined, the problem becomes how to detect and determine the intensity of the exposure. To do this, the Incident Safety officer or designee collects samples of air or uses direct-reading instruments. Every effort must be made to obtain samples that represent the worker’s exposure. Currently there is no effective direct-reading instruments for biological agents. All biological monitoring will involve colleting a sample (air, soil, wipe swath, etc…) and having the sample analyzed by a laboratory for the presence of the desired biological agent. A chemical agent may not be the agent of concern during a deployment, however deployment activities may introduce a chemical agent into the deployment area and necessitate monitoring. Physical agent such as heat/cold issues are a possibility when working outdoors.  Also most direct reading monitoring equipment is agent specific and has a concentration range for which it is accurate. Once the Site Safety Officer has completed the HAPS Form 3 (Agents) it is recommended that they confer with an SHEWB IH to assure the correct equipment is to be utilized and available. HASP Form 5 (Monitoring Equipment) is than to be completed to assure the instruments are calibrated and maintained as needed.

There are multiple objectives to monitoring. They include determining:

• Baseline: What is the range and distribution of worker exposure(s);
• Diagnostic: Sources and tasks that pose the greatest potential exposures in the workplace;
• Compliance: Is this workplace in compliance with OSHA standards;

To decide what constitutes a representative sample, five basic questions must be answered:

• What to sample for
• Where to sample
• Whom to sample
• How long to sample
• How many samples to take
• When to sample (day/night, or what month/season)

What to sample for will be determine by environment (heat/cold, radiation, noise), by the agent of concern (is the deployment due to a chemical spill), and agents APHIS will use during the deployment (what chemicals are being utilized as part of the deployment, are radioactive sources being used). The ACGIH’s TLV guide should be utilized to aid in these determinations as well as the SHEWB IH (if needed).

Once the above is determined, a sampling plan is developed which will give an accurate overview of workers’ exposure. Each sample is acquired at a particular location over a specific time interval. By its nature, sampling can only provide a snap shot of the actual situation. The more snap shots taken, the easier it is to create the big picture and the more accurate its results. By determining a statistically significant number of samples (a minimum of three), and taking sampling from a representative number of employees (not just one work area or job title), this overall picture is formed.