The Occupational Safety and Health Administration (OSHA) can seriously affect any Contractor or construction project. Compliance with OSHA regulations can be time-consuming and tedious, but it is essential to maintain a viable position in the construction industry. This month, as always, we report on recent developments in the world of OSHA.

Safety Procedures May Make Trench Atmosphere Less Dangerous

Hazardous atmospheres are a silent killer. In most cases injured employees won’t even know what happened when they are hurt by a harmful substance.

Enclosed on all sides but one, trenches are a great place for gases to accumulate. Airflow is often limited, and gases have nowhere to go but to sit in deep trenches. Even if the gas is lighter than air, the gas still needs to pass by the employees working in the trench.

What can be done?

In an effort to help employers make the work environment safe for employees, OSHA provides a Guide for Daily Inspection of Trenches and Excavations on its website ( The Guide includes some procedures that, if followed, save lives. You will find this checklist at the website:  What is required?

OSHA requirements provide for the testing of hazardous atmospheres and, when necessary, the use of specific controls to eliminate any threat a poisonous gas may pose. The key here is to conduct testing and discover the danger before the employee enters the trench.

OSHA standard 1926.651(g)(1)(i) requires an employer to test the atmosphere of a trench where there is an oxygen deficiency or where a “hazardous atmosphere exists or reasonably could exist.” Examples of such areas include “excavations in landfill areas or excavations in areas where hazardous substances are stored nearby.” The testing requirement, however, only applies “before employees enter excavations greater than 4 feet in depth.”

Once a hazardous atmosphere is detected, the employee must use specific controls to lower the risk posed by the presence of the dangerous substance. The controls [1926.651(g)(1)(ii-iv)] include additional respiratory protection, ventilation, and continued testing of the atmosphere that “shall be conducted as often as necessary to ensure that the atmosphere remains safe”:



Adequate precautions shall be taken to prevent employee exposure to atmosphereDtaining less than 19.5 percent oxygen and other hazardous atmospheres. These precautions include providing proper respiratory protection or ventilation in accordance with subparts D and E of this part respectively.


Adequate precaution shall be taken such as providing ventilation, to prevent employee exposure to an atmosphere containing a concentration of a flammable gas in excess of 20 percent of the lower flammable limit of the gas.


When controls are used that are intended to reduce the level of atmospheric contaminants to acceptable levels, testing shall be conducted as often as necessary to ensure that the atmosphere remains safe.

Inspections are also required on an asneeded basis where there is evidence of a possibly hazardous atmosphere. OSHA standard 1926.651(k)(1) requires the employer to have a competent person inspect the area “prior to the start of work and as needed throughout the shift.”



What happens when an inspection is not performed?

Failure to inspect for a hazardous atmosphere can create a very dangerous situation for any employee who may be exposed to toxic gases. One example of just how quickly a hazardous atmosphere can injure or kill an employee is found in Secretary of Labor v. EMCON/OWT, Inc., OSHRC Docket No. 04-1406 (December 8, 2005).

EMCON was hired to expand an existing landfill gas collection system at a large landfill located in Okeechobee, Florida. A crew of EMCON employees was charged with the task of cutting a leachate clean-out pipe in order to complete the final tie-in for the gas extraction system.

When one laborer cut into the pipe, his chain saw stopped working. The employee returned with a Saws-All and reentered the trench, commenting on a “foul odor.” The laborer left the trench, and his foreman entered the trench to make the cut into the pipe. The foreman also stopped before cutting the pipe and commented on the odor.

A second laborer then bent down to cut the pipe and immediately commented on the smell. A third laborer entered the trench, looked at the pipe, and said, “Something is not right.” Just then the third laborer passed out, the second laborer “was bleary-eyed and his legs were buckling,” and the foreman passed out as he attempted to help the third laborer out of the trench. That’s two unconscious employees, one who was vomiting, and a fourth who was foaming at the mouth and later died from his injuries.

According to OSHA, EMCON failed to take adequate precautions to protect the employees from the hazardous atmosphere, as required by 1926.651(g)(1)(ii). OSHA also alleged that EMCON vacated the trench to let it air out but failed to conduct the necessary air sampling prior to allowing employees back in the trench, as required by 1926.651(g)(1)(iv). Finally, OSHA alleged that EMCON failed to have a competent person conduct air sampling to detect a hazardous atmosphere, as required by 1926.651(k)(1).

The issue came before the Occupational Safety and Health Review Commission, which vacated the first two citations. Why? Because the trench was only about three feet deep, and inspections and controls are necessary only if a trench is at least four feet deep. The Administrative Law Judge determined that 1926.651(g)(1), when read in its entirety, did not require EMCON to test the atmosphere before the employees entered the three-foot deep trench.

The Administrative Law Judge, however, determined that EMCON violated 1926.651(k)(1) by failing to have a competent person inspect the trench. According to the court, section 1926.651(k)(1) requires two inspections. First, a competent person must inspect the trench prior to the start of work at the beginning of the day.

EMCON’s competent person performed the necessary inspection at the start of the day.

The second inspection must be performed “after every rainstorm or other hazard increasing occurrence.” This second inspection is required “when employee exposure can be reasonably anticipated.”

The court determined that the “other hazard increasing occurrence” was the point where EMCON made the cut into the leachate pipe. “Reasonable anticipation of employee exposure was raised by three incidents over a span of approximately 20 minutes: the gas chainsaw stopped, indicating a lack of oxygen in the atmosphere; a strong, unpleasant odor arose from the leachate pipe; and each crew member suffered immediate physical discomfort upon entering the excavation to make the second cut.” This is the point when EMCON, according to the court, should have tested the atmosphere.

EMCON appealed this result and lost. The appellate court, however, stated that it was a “close case” and EMCON has requested an appeal in the United States Supreme Court. At press time the Court had not yet determined if it would hear the case.

If an inspection had been conducted in the EMCON case, it probably would have saved a life. EMCON had gas meters in its truck. All someone had to do was test the foul-smelling air that emanated from the cut pipe. Had this been done, the employee might still be alive today.