CNG Emergency Procedures and Response 4

Question 1

In the United States, a CNG fuel release exceeding reportable quantity thresholds must be reported to:

Accepted Answer

The National Response Center (NRC)

Answer

The National Response Center (NRC) is the federally designated 24-hour reporting point for all significant hazardous material releases, including CNG.

Question 2

If a CNG vehicle overturns with an active gas leak, responders should:

Accepted Answer

Isolate the area and eliminate all ignition sources

Answer

Isolating the area and eliminating ignition sources prevents the gas from reaching flammable concentration near an ignition point.

Question 3

What physical property makes CNG inherently safer than gasoline in an outdoor spill scenario?

Accepted Answer

CNG is lighter than air and disperses upward rather than pooling

Answer

Being lighter than air, CNG rises and dilutes outdoors rather than pooling on the ground and spreading laterally like gasoline.

Question 4

The primary life-safety hazard during a CNG vehicle accident involving fuel release is:

Accepted Answer

Fire or explosion resulting from ignition of released gas

Answer

Natural gas is highly flammable within its 5–15% flammability range, making fire and explosion the dominant life-safety threat during a CNG release.

Question 5

At what concentration is natural gas (methane) classified as Immediately Dangerous to Life or Health (IDLH)?

Accepted Answer

150,000 ppm

Answer

NIOSH establishes the IDLH for methane at 150,000 ppm (15% by volume), which corresponds to the lower explosive limit where asphyxiation and explosion risks converge.

(CNG) Compressed Natural Gas Practice Test

(CNG) Compressed Natural Gas Practice Test

CNG Emergency Procedures and Response 4