CHEMICAL LABORATORY SAFETY TAKING THE LONG VIEW: CARCINOGENS AND RELATED HEALTH HAZARDS

Objectives

Taking the Long View: Carcinogens and Related Health Hazards: American Chemical Society chemical safety video courses

Introduction

Over the last several decades, chemical workers have rightfully become concerned about potentially carcinogenic and mutagenic chemicals, as well as those that cause reproductive and developmental disorders.   Carcinogens are substances implicated in cancer; mutagens are chemicals that may cause genetic damage; and reproductive and developmental toxins can affect the success and outcome of reproduction.

Most materials, natural or manmade, used in research laboratories have not been tested for carcinogenicity.   However, because of the profound effects of cancer on human mortality and morbidity, the Occupational Safety and Health Administration's (OSHA) Laboratory Standard refers to compounds known to pose the greatest danger of cancer as "select carcinogens", and requires that they be handled as "particularly hazardous substances" in a designated area.    Mutagens and reproductive toxins are also included in this category, as are highly toxic materials.

The OSHA Laboratory Standard defines a "select carcinogen" as any substance that meets one of the following criteria:

• It is regulated by OSHA as a carcinogen.

• IIt is listed as "known to be a carcinogen" in the latest Annual Report on Carcinogens issued by the National Toxicology Program.

• It is listed under Group 1 ("carcinogenic to humans") by the International Agency for Research on Cancer (IARC).

• It is listed by IARC as "probably carcinogenic to humans" or "possibly carcinogenic to humans", or by NTP as "reasonably anticipated to be a carcinogen", and causes statistically significant tumor incidence in experimental animals at specific inhalation, application, or ingestion exposures identified in the Laboratory Standard.

Chemicals that have not been tested for carcinogenicity should be considered suspected carcinogens if, according to expert opinion, they are structurally similar to chemicals that have been proven carcinogenic.   Prudence dictates that potential mutagens and reproductive toxins be treated with the same caution.

Measures for handling "particularly hazardous substances" are designed to provide chemical workers with multiple layers of defense.    These measures are contained in four cardinal rules:

• Anticipation - learn as much as possible about the chemical plan and how to use it.

• Recognition - understand the conditions under which the chemical may be hazardous, e.g., high temperature, presence of water, unprotected skin.

• Evaluation - determine the engineering controls and work practices necessary to safely use the chemical, e.g., hoods, eye wash stations, safety showers, special protective clothing, designated areas.

• Control - implement and use the safeguards required to control the hazards of the chemical, e.g., containment, storage, administrative controls.

Develop a peer-reviewed safety protocol for any new process to ensure that proper and appropriate safety, handling, storage, transportation, shipping, and disposal techniques are in place before work begins.

Important Concepts

• "Select carcinogens" are chemicals known to pose the greatest danger of cancer.   Select carcinogens are regulated by the U. S. Occupational Safety and Health Administration (OSHA), and are classified as carcinogens by the National Toxicology Program in the Annual Report on Carcinogens and by the International Agency for Research on Cancer.   They require special handling procedures, and may be used and stored in a designated area only.

• The size of a designated area depends on how much hazardous chemical is being used or stored, where the area is located, the type of work being performed, and who else might be exposed in the event of a release.

• To work safely with carcinogens and related hazards, you must anticipate the potential hazards, recognize when and how a specific hazard arises, evaluate the level of hazard and determine the practices and procedures necessary for working safely, and control or contain the hazard via engineering and administrative controls, operational practices, and the use of appropriate personal protective equipment and clothing.

• Always read the Material Safety Data Sheet (MSDS) for any chemical you use in the laboratory.   Note particularly the recommended precautions and controls for working with carcinogenic or related chemicals, especially personal protective equipment and spill cleanup procedures.

• Develop a peer-reviewed safety protocol for any new process in a lab.

• Test the area of a spill after cleanup to ensure adequate decontamination.