How Do Hazardous Chemical Classifications Affect Clean-Water Plants?

How Do Hazardous Chemical Classifications Affect Clean-Water Plants?
Signal words and a number classification are tied to the GHS hazard index.

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The Globally Harmonized System for Classification and Labeling of Chemicals is a logical, comprehensive and international approach to: 

  • Defining the three hazards of chemicals: health, physical and environmental.
  • Creates a process in which to classify chemical hazards by using available data on the chemicals.
  • Establish a globalized way to communicate hazard information and protective measures through labels and the new Safety Data Sheets.

Under OSHA, the Hazard Communication standard is mandatory for all employers that have chemicals that fall under 1910.1200(b)(5). Wastewater facilities have several of these chemicals for laboratory testing, disinfection, carbon sources or other processes so GHS changes will affect all facilities, not just those within a state OSHA program.

The GHS is a brainchild of a United Nations special committee from 1992. At that time compliance was expected by 2000, but the first GHS document wasn’t published until 2003. However, only portions of the program have been implemented internationally. In the U.S., agencies such as OSHA, DOT, Department of Agriculture, and others are rapidly transitioning to the labeling and hazard classification.

Utility workers are regularly in contact with various amounts of hazardous chemicals. Some laboratory procedures use reagents, acids and alkaline to yield process control readings. If there was an accident in the laboratory, how would operators know how to protect themselves, how to properly clean spills, or even how to correctly store and handle these chemicals? These answers are found in the Material Safety Data Sheet (MSDS) provided by the chemical manufacturer.

The GHS will change MSDS to SDS (Safety Data Sheet) with mandated and uniformed sections for global chemical manufacturers. Manufacturers will have to include the following:

  • Product name and emergency number
  • Potenial hazards and signal word
  • Ingredients, chemcial make-up of product and common name
  • First-aid measures
  • Firefighting measures
  • Procedures for accidental release
  • Handling and storage
  • Exposure control/personal protection
  • Physical and chemical properties (appearance, odor threshold, pH)
  • Possible hazardous reactions and incompatible materials
  • Toxicological information
  • Date of preparation/last revision 

Other non-mandatory information could include ecological data, disposal requirements, transportation suggestions and regulatory information.

Another major change in the new system is the shift from the National Fire Protection Association/Hazardous Material Identification System rating and color-coding chemicals to the Hazard Communication System pictogram. A “4” in the current system means a severe hazard in the color category. Now a “4” is only a slight hazard in the GHS. Workers that have always used the NFPA/HMIS system will need time to adjust to this change.

To add insult to injury, the color code is not being replaced with pictograms as presented below.

Each pictogram is associated with a hazard that the chemical manufacturer identifies as present or suspected in their product.

A signal word — Danger or Warning — must follow the pictogram, including a statement of why the product has that particular signal word. These words and the number system are tied to the GHS hazard index as shown on the following charts from OSHA.

On the health toxicity scale LD50 indicates that out of 100 test animals 50 or half died at a specific dosage in mg/kg. Therefore, the more toxic the chemical, the lower the dose needed to kill half of the test subjects. So, the GHS scale ranks No. 1 as a lower dose and No. 5 as a higher dose. This chart offers a visual depiction of the GHS scaling:

In addition, flammable products follow a temperature scale in Celsius, boiling point and flashpoints.

According to OSHA, “the boiling point of a liquid at a pressure of 14.7 pounds per square inch absolute. This pressure is equivalent to 760 millimeters of mercury (760 mm Hg). At temperatures above the boiling point, the pressure of the atmosphere can no longer hold the liquid in the liquid state and bubbles begin to form. The lower the boiling point, the greater the vapor pressure at normal ambient temperatures and consequently the greater the fire risk.”

OSHA defines flashpoint as “the minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid. The flashpoint is normally an indication of susceptibility to ignition.”


Chemical labeling is changing to the new system, though utilities can use the old labeling system for secondary containers. However, if they choose to use both systems, then workers must be trained on both systems. Labels will now look as follows:

Utilities must create a hazard communication program to compile these changes and all information regarding handling, use, storage and cleanup. Employees have the right to know which hazardous materials they are working around. A written HazCom program can be completed by a consultant or an in-house safety and compliance officer.

Worker training is an important part of this standard. Training is required when a worker is introduced to a hazardous chemical, when their roles change to working with these chemicals, and annually. Training requirements for the Hazard Communication program are 29 CFR 1910.1200(h). Here is the compliance schedule for the GHS transition:

Some workers will be confused about handling spills, performing cleanups, or choosing proper PPE, so minimize the confusion with effective training and awareness.

About the Author

Sheldon Primus is a Class A licensed wastewater operator with more than 18 years of industry experience. He is a Certified Occupational Safety Specialist, authorized OSHA outreach instructor, and holds master’s degrees in public administration and environmental policies.

He has held positions as a laboratory operator, chief operator, plant superintendent, safety and compliance officer, and industrial pretreatment coordinator.

Primus is CEO of Utility Compliance Inc. based in Port St. Lucie, Fla., which helps utilities in industrial pretreatment and risk management program compliance, water and wastewater CEU training, as well as occupational safety program development and OSHA outreach training for general industry and construction. He is also an online adjunct instructor for the Environmental Science Department at Florida Gateway College. He can be reached at or 888/398-0120.


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