Background
Extended Public Safety Power Shutoffs (PSPSs) are increasingly common in response to weather conditions that present risk for wildfires from powerline damage. We examined trends in Emergency Medical Services (EMS) call volume during a county-wide PSPS in Marin County (October 25-31, 2019) to evaluate the health impacts.

Methods
EMS records county-wide were used to describe total EMS responses, by age and disposition, and specific causes. Daily frequencies and proportions were compared between October 27-29 (days one-three), when the largest numbers of meters were de-energized, and daily two-year averages using chi-squared and Welch’s T-tests.

Results
Responses nearly doubled on days one (n=94) and two (n=99) compared to two-year averages (n=49). The average visitor age was higher on days one to three (range 68-69) as compared to two-year averages (61 years;p<0.005). Responses due to respiratory-related events (range 5-9% vs. 2%) and medical-device issues (range 0-5% vs. <1%) were elevated during PSPS (p>0.05). Environmental-related injuries were elevated during day two (10% vs. 2%;p=0.09). Though non-significant, individuals were more likely to refuse transport to a hospital during PSPS (range 7-8% vs. 3%; p>0.05). Fall-related events were not elevated during PSPS (p>0.05; range 15-25% vs. 21%).

Discussion
These results indicate that PSPS conditions may lead to increased EMS usage, particularly among older adults, and that more patients may have refused transport to a hospital during PSPS. Decisions to initiate power shutoffs should be carefully weighed with other public health risks, and multi-disciplinary collaborations are needed to reach medically-vulnerable residents affected by these outages.