Types of Sampling Defined
OSHA Releases Data Detailing Worker Exposure to Toxic Chemicals

OSHA is releasing 15 years of data providing details of workplace exposure to toxic chemicals, and issuing a directive on protecting non-English speaking workers from hazards.

Comprised of measurements taken by its compliance officers during the course of inspections, the data offers insights into the levels of toxic chemicals commonly found in workplaces, and, into how chemical exposure levels to specific chemicals are distributed across industries, geographical areas and time. It includes exposure levels to hazardous chemicals including asbestos, benzene, beryllium, cadmium, lead, nickel, silica and others.

“This information, in the hands of informed, key stakeholders, will ultimately lead to a more robust and focused debate on what still needs to be done to protect workers in all sectors, especially in the chemical industry,” said Assistant Secretary of Labor for OSHA Dr. David Michaels.

OSHA says that for comparison against many occupational health standards, it is necessary to measure quantitative exposure levels in the workplace.

Depending on circumstances, there are various sampling technologies, procedures, and philosophies to measure airborne chemical concentrations to workers. Exposure assessment data can be compared to established standards to help determine if the exposure is acceptable.

An understanding of the relationship between the amount of a chemical present in the workplace and the biological response to that chemical is necessary to establish acceptable exposure levels. Established standards based on science, technology, and economics allow for the evaluation of worker exposure against an established and acceptable benchmark.

Common types of sampling include:

Integrated sampling: Uses technologies that provide integrated sampling over time. Samplers may be changed several times during a work shift, which requires additional statistical averaging. Integrated sampling results for an entire eight-hour work shift yield an eight-hour time weighted average sample that can be compared directly to an 8-hour TWA standard.

Integrated results may represent samples that were changed several times during the workshift and eventually combined into a cumulative time weighted average. As a result, individual sample values may not be directly comparable to levels listed in OSHA’s Permissible Exposure Limits (PEL).

Direct reading or instantaneous sampling: Uses technologies that provide immediate results or short-term integrated results and are used to compare airborne concentrations against ceiling or short-term standards.

Breathing zone sampling: Sample is obtained in the breathing zone of a specific worker.

Area sampling: Sample is obtained in an area representative of a process, a “worst case,” or multiple workers’ exposure.

Bulk sampling: A bulk sample of a raw material or contaminant is taken to determine its chemical make-up. Bulk samples are used individually or in conjunction with personal or area samples to help interpret the level of worker risk. Common types of occupational standards for acceptable exposure to chemicals in air include:

TWA — Time Weighted Average: Represents the allowable average chemical concentration in air for a given period of time. Historically, a work shift has been eight hours per day and this is often expressed as the allowable 8-hour TWA.

C – Ceiling: Exposure to concentrations in excess of this value should not be permitted regardless of duration.

OSHA’s data: OSHA takes industrial hygiene samples as part of its compliancemonitoring program. Its chemical exposure data represent personal, area, and bulk samples for various airborne contaminants. For more on this, go to www.osha.gov/opengov/healthsamples.html.

OSHA also has issued an enforcement memorandum directed at protecting Latino and other non-English speaking workers from workplace hazards. It directs compliance officers to ensure they check and verify that workers are receiving OSHA required training in a language they understand.

OSHA requires that employers provide training to their workers on certain job hazards and safe methods for performing work. Investigators will now check and verify that training was provided in a language and vocabulary that the workers understand.

Another step in empowering the public with information on chemicals in their communities, the EPA has added more than 6,300 chemicals and 3,800 chemical facilities regulated under the Toxic Substances Control Act (TSCA) to a public database called Envirofacts.

It includes facility name and address information, aerial image of the facility and surrounding area, map location of the facility, and links to other EPA information on the facility, such as EPA’s inspection and compliance reports that are available through the Enforcement Compliance History Online (ECHO) database.

The EPA is also adding historic facility information for another 2,500 facilities. FSM