By CHRISTINA A. CASSIDY and ALI SWENSON, Associated Press

ATLANTA (AP) — Two ballot boxes in the Pacific Northwest were damaged in a suspected arson attack just over a week before Election Day, destroying hundreds of ballots at a location in Vancouver, Washington.

On the other, in Portland, Ore., a fire suppression system reportedly worked to contain the fire and limited the number of damaged ballots to three. Authorities are reviewing surveillance footage as they try to identify who is responsible.

Here’s what happened, how rules and security measures around drop boxes vary across the country, and how election conspiracy theories have undermined confidence in their use.

What do we know?

Police said incendiary devices started the pit fires in Portland and Vancouver. Authorities said evidence showed the fires were linked and that they were also linked to an incident on Oct. 8 when an incendiary device was placed in a different box in Vancouver.

Multnomah County Elections Director Tim Scott said his office plans to contact the three voters whose ballots were damaged in Portland to help them get replacements.

In Vancouver, hundreds of ballots were lost in a ballot box at Fisher’s Landing Transit Center when the transfer box’s fire suppression system did not work as intended. Clark County Auditor Greg Kimsey said the box was last emptied at 11 a.m. Saturday. Voters who subsequently dropped their ballots there are urged to contact the office to obtain a new one.

The office will increase the frequency with which it collects ballots and change collection times in the evening to prevent ballot boxes from remaining full overnight, when vandalism is more likely to occur.

Kimsey described the alleged arson as “a direct attack on democracy.”

When and where can delivery boxes be used?

Drop-in boxes have been used for years in states like Colorado, Oregon, Utah and Washington, where ballots are mailed to all registered voters.

They grew in popularity in 2020 during the COVID-19 pandemic as election officials sought options for voters who wanted to avoid crowded polling places or were concerned about mail delays.

In all, 27 states and the District of Columbia allow ballot boxes, according to data collected by the National Conference of State Legislatures. Another six have no specific law but allow local communities to use them.

Placement can vary greatly. In some communities, they are located in public buildings, available only during business hours. Elsewhere, they are outside and accessible at all hours, usually with video surveillance or someone watching.

Sporadic problems have arisen over the years.

In 2020, several boxes were hit by vehicles and one in Massachusetts was damaged by fire. In this case, most ballots were legible enough for voters to be identified and replacements sent. A box was also set on fire in Los Angeles County in 2020.

How should they be insured?

The US Cybersecurity and Infrastructure Agency advises state and local election officials to place the boxes in convenient, high-traffic areas familiar to voters, such as libraries and community centers.

If the booths are not staffed, they should be secured and locked at all times, located in well-lit areas and monitored by video surveillance cameras, the guidance states. Many are fixed to the ground, monitored by cameras, or locked up in public buildings during business hours, where they can be monitored.

How have conspiracy theories contributed to concerns about drop boxes?

Ballot boxes have been in the spotlight for the past four years, targeted by right-wing conspiracy theories who falsely claimed to be responsible for massive voter fraud in 2020.

A debunked film called “2,000 Mules” amplified the claims, exposing millions of people to a baseless theory that a ballot collection operation was depositing fraudulent ballots into drop boxes in the dark of night.

A Associated Press poll of state election officials in the US found that there were no widespread problems associated with delivery boxes in 2020.

The paranoia about drop boxes continued until the 2022 semester, when armed vigilantes began showing up to monitor them in Arizona and were restricted by a federal judge. This year, the conservative group True the Vote launched a website that hosts live streams of citizens with ballot boxes in various states.

In Montana, where a key U.S. Senate race is on the ballot, Republicans recently resorted to a bogus ballot-tampering claim to cash in on doubts about the election process.

How have states responded since the 2020 election?

Republican lawmakers in several states have sought to tighten rules on mail-in voting after the 2020 election, and much of their attention has focused on the use of ballot boxes.

Since then, six states have banned them: Arkansas, Mississippi, Missouri, North Carolina, South Carolina and South Dakota, according to research by the Voting Rights Lab, which advocates for expanded voting access.

Other states have restricted its use. That includes Ohio and Iowa, which now only allow one drop box per county, according to the Brennan Center for Justice.