MFRI HAZMAT STUDY FINAL TEST 2026 QUESTIONS WITH
CORRECT ANSWERS GRADED A+
● Threshold Limit Value (TLV). Answer: the point at which a hazardous material begins to
affect a person
● Permissable Exposure Level (PEL). Answer: the established standard limit of exposure to
a hazardous material
● threshold limit value/short term exposure limit. Answer: the maximum concentration of
a hazardous material that a person can be exposed to in 15 minute intervals, up to four time
per day, without experiencing irritation or chronic or irreversible tissue damage
● threshold limit value/time weighted average. Answer: maximum airborne concentration
of a hazardous material that a worker should not be exposed to, even for an instant
● threshold limit value/skin. Answer: indicates that direct or airborne contact with a material
could result in possible and significant exposure from absorption through the skin, mucous
membranes, and eyes.
● Recommended exposure level (REL). Answer: a value established by the National
Institute for Occupational Safety and Health and is comparable to OSHAs PEL.
● Immediate danger to life and health (IDLH). Answer: an atmospheric concentration of a
toxic, corrosive, or asphyxiant substance poses an immediate threat to life or could cause
irreversible or delayed adverse health effects.
● safe atmosphere. Answer: no harmful hazardous material effects exist, so personnel can
handle routine emergencies without donning specialized PPE.
● unsafe atmosphere. Answer: a hazardous material that is not longer contained has
created an unsafe condition or atmosphere. A person who is exposed to the material for long
enough will probably experience some form of acute or chronic injury
● dangerous atmosphere. Answer: serious, irreversible injury or death can occur in the
environment without PPE
● yellow environments. Answer: are transitional, whereby hazard is increasing, and some
level of PPE is required
CORRECT ANSWERS GRADED A+
● Threshold Limit Value (TLV). Answer: the point at which a hazardous material begins to
affect a person
● Permissable Exposure Level (PEL). Answer: the established standard limit of exposure to
a hazardous material
● threshold limit value/short term exposure limit. Answer: the maximum concentration of
a hazardous material that a person can be exposed to in 15 minute intervals, up to four time
per day, without experiencing irritation or chronic or irreversible tissue damage
● threshold limit value/time weighted average. Answer: maximum airborne concentration
of a hazardous material that a worker should not be exposed to, even for an instant
● threshold limit value/skin. Answer: indicates that direct or airborne contact with a material
could result in possible and significant exposure from absorption through the skin, mucous
membranes, and eyes.
● Recommended exposure level (REL). Answer: a value established by the National
Institute for Occupational Safety and Health and is comparable to OSHAs PEL.
● Immediate danger to life and health (IDLH). Answer: an atmospheric concentration of a
toxic, corrosive, or asphyxiant substance poses an immediate threat to life or could cause
irreversible or delayed adverse health effects.
● safe atmosphere. Answer: no harmful hazardous material effects exist, so personnel can
handle routine emergencies without donning specialized PPE.
● unsafe atmosphere. Answer: a hazardous material that is not longer contained has
created an unsafe condition or atmosphere. A person who is exposed to the material for long
enough will probably experience some form of acute or chronic injury
● dangerous atmosphere. Answer: serious, irreversible injury or death can occur in the
environment without PPE
● yellow environments. Answer: are transitional, whereby hazard is increasing, and some
level of PPE is required
