Amphetamines and Severe Heat Illness in Workers: OSHA Cases, 2010–2019

Background

Workers develop hyperthermia when heat stress — environmental heat plus the body's heat from physical work — raises core temperature. Amphetamines, central nervous system stimulants, can cause hyperthermia on their own or add to other risks. During 2010–2016, OSHA's Office of Occupational Medicine and Nursing (OOMN) found three workers who died of hyperthermia and tested positive for methamphetamine.

The review

OOMN reviewed all medical records and investigation files that OSHA offices sent it from January 1, 2010 to August 31, 2019, gathered during OSHA inspections.

• Definition: severe hyperthermia meant a very high temperature — core ≥104°F (40°C) or peripheral ≥102°F (38.9°C) — with death or serious brain dysfunction such as coma or seizure (or, for deaths without a measured temperature, a medical examiner's finding that heat caused or contributed to death).
• Cases: 111 heat-related illnesses, 46 with severe hyperthermia (38 fatal, eight not).
• Toxicology was available for 34 (73.9%) of the 46 — and nine (26.5%) tested positive for an amphetamine-class drug.

The nine workers

All were men aged 18–47 (median 30) in industrial jobs in eight states, on warm days in summer or late spring, with a maximum heat index of 86°F to 107°F (median 97°F).

• Outcomes: seven died and two survived life-threatening illness. Peak temperatures reached 103°F to 110.6°F (39.4°C to 43.7°C). One man, found dead, had no temperature taken; the medical examiner judged heat a major contributor after strenuous work on a hot day.
• Illicit use appeared likely in seven: three had methamphetamine in postmortem blood, and four screened positive for amphetamines without a prescription. One of these died of heat on his first day at a new job; a coworker told OSHA the supervisor had handed out pills that looked like a prescription amphetamine before the shift.
• Prescribed use: two took prescription amphetamines for ADHD — and both died.
• Other substances (THC, benzodiazepines, an opioid and others) were judged not to have caused the hyperthermia.

What to do

• Know the risk: NIOSH links amphetamines to heat intolerance. Workers and supervisors should know that amphetamines, physical exertion and heat can act together.
• Workers: don't use illicit amphetamines to stay alert or boost performance, especially in heat; workers with stimulant use disorders should get support.
• Prescribers: take an occupational history from patients on amphetamines to talk about heat safety.
• Employers: put comprehensive heat stress controls in place, as recommended by NIOSH and OSHA.

Sources

Based on "Notes from the Field: Amphetamine Use Among Workers with Severe Hyperthermia — Eight States, 2010–2019," by Andrew S. Karasick, Richard J. Thomas, Dawn L. Cannon, Kathleen M. Fagan, Patricia A. Bray, Michael J. Hodgson and Aaron W. Tustin, Occupational Safety and Health Administration, Morbidity and Mortality Weekly Report, Centers for Disease Control and Prevention; a work of the United States government in the public domain.