A combustible gas indicator (CGI) gives a reading for an atmosphere containing which of the following for toluene?

The correct answer is based on the understanding that a combustible gas indicator (CGI) measures the concentration of flammable gases in the atmosphere, often given in percentage of the lower explosive limit (LEL). For toluene, the LEL is approximately 1.2% by volume in air.

When the CGI registers a reading of 2.0, this indicates that the concentration of toluene in the atmosphere is at a level that is 2.0% of the LEL, which would mean the atmosphere is potentially hazardous but not yet at a level that could lead to an explosion. This reading suggests that there's a moderate presence of toluene, prompting further investigation and monitoring to ensure safety protocols are followed.

It's essential to understand that reading percentages based on LEL measurements are critical in determining the necessary safety precautions during hazmat operations. Higher readings would increase the urgency for immediate action to mitigate risks, while lower readings may indicate a safer environment relative to the LEL.