JACKSONVILLE, Fla. -- Come rain or sleet or snow, you'll get your mail. But ...

"Right now, letter carriers are upset because the postal service has changed the letter carrier's starting times to anywhere between 8:30 and 9 o'clock in the morning," said Bob Henning, President of the North Florida Letter Carriers Union Local Branch 53.

Henning is a retired letter carrier after 35 years. He said he's seen carriers out as late as 7:30 p.m.

"It's very hazardous for us to be out there delivering mail in the dark," he said.

A Central Pennsylvania newspaper reports a local postmaster is in the process of providing all letter carriers with hands-free led headband lights for after sunset deliveries.

Henning said about a week ago, a letter carrier was bitten by a dog in Atlantic Beach while on an after dark delivery.

According to ABC News, a 26-year-old on-duty letter carrier for the USPS in Maryland was shot and killed while on his route around 7 p.m. in late November. There's a $100,000 reward for information leading to an arrest.

"Our letter carriers are getting concerned for their safety as well as the customer's safety," Henning said.

Henning said it began in November 20th. First Coast News asked him his thoughts on why.

"Mostly because of short short staffing but this time of year, we also have a lot of heavy mail volume," he said.

Henning said the best thing you can do to help your mail carrier if they do come after dark, is to leave your porch light on for them.

Polly Gibbs, spokesperson for the United States Postal Service said:

"Letter carriers have always delivered mail in the dark in standard time zones, and in the winter when it gets dark as early as 4:00 p.m. in certain areas of the country. In Alaska, for several months out of the year, letter carriers are delivering in the dark for much of the day. Over the last four or five years, carrier start times have become later due to a decrease in manually cased mail and less office time required to prepare for street delivery duties. This has been a gradual process, as the way we process mail has been changing over the years."

Gibbs said since fiscal year 2011, there have been four carriers who were murdered while on duty. Gibbs said one of them was in the morning shortly after opening the Post Office, another while delivering a route in the mid-afternoon, another during the afternoon and one in the evening after 7 p.m.

Gibbs said the Postal Service and Inspection Service work together to give employees safety guidance, including tips on how to reduce the chance of being assaulted or robbed.