To perform our jobs, we need to move stone, 

rocks, and boulders. For over a century, blasting 

has been the best method for doing this. Blasting 

breaks rocks into sizes small enough for our 

equipment to handle.

When we blast, you could be injured or killed if 

you are in the wrong place. To ensure your safety, a 

BLASTER-IN-CHARGE carefully calculates a zone 

around the blast where rocks might land. This zone 

is called the BLAST AREA. Before a blast, we post 

guards at all entry points and stop all traffic going 

into the area. We clear out all people, equipment, 

and large animals, and we make sure that nothing 

and no one has strayed into the area. No one is 

permitted in the blast area when we shoot. That is 

why it is important for us to know where you are. 

That is why we ask you to sign in when you arrive.

 Inside the blast area, debris from blasting 

travels fast. You won’t be able to duck it or outrun 

it. By placing yourself within the blast area during 

the time of the shot, you are placing yourself in a 

lot of danger.

However, even if you are not inside the blast 

area, be careful. FLYROCK is debris that travels 

or rolls outside the blast area. This does not happen

often, but stray rocks have been known to land a 

half mile away. If 

you are that far from 

a blast, you can look 

to the sky. If you see 

material or objects in 

the sky, you should 

take cover fast. Safe 

cover is not behind 

a car’s windshield, 

and it is not beneath 

trees. Even if you 

are outside the blast 

area, stay alert and 

keep your eyes open.

Blasts are carefully controlled. Nothing will 

appear in the sky unless something has gone wrong. 

This event has not happened often, but we want you 

to be safe while on our site. 

Our employees understand that blasting is 

serious business. The blaster will set off an earlywarning signal at about 5 - 10 minutes before the 

blast, a final-warning signal shortly before the blast, 

and then an all-clear signal after the blast when it 

is safe. Our employees know the blast signals that 

we use and know what to do when they hear them. 

We want to make sure that you, our 

visitor on site, also know what to do 

when you hear our signals. 

Visitor’s Hazard ALERT

The hole in this tree was 

the result of a blast in 

Pennsylvania in 2002.

A miner and a visitor at a blast site 

in New Mexico thought that they 

had more time to protect themselves 

before the blast. But this blast was 

not well controlled. The visitor was 

hospitalized for months. The miner 

died at the scene.

When you hear this signal, the blasting process has 

begun. The holes have been loaded, the initiation 

system is tied-in, and the final security checks are 

being made. If you think you may still be inside 

the blast area, you need to get out immediately 

– if you know where “out” is, and if you know 

that you won’t have to travel past the blast area. 

If you don’t know for sure where the blast area is 

or how to get out, then you need to sound your 

car’s horn or shout and hope someone can hear 

you or see you. 

1. The early warning blast signal: 

This signals that the blast is coming in a minute 

or so. If you are still in the blast area at this time, 

take cover and shout or sound your car horn 

and let people know you are there. Make your 

presence known and take shelter. Stay sheltered 

until the “all-clear” is signaled or until someone 

comes to get you. Even beyond a 1-minute 

warning, the blast can be stopped if someone is 

spotted in the blast area.

2. The final blast warning signal: 

When the all-clear signal sounds, it is safe to 

return to the blast area. The all-clear signal 

may not happen right after the blast because the 

blaster-in-charge must inspect 

the area to make sure that all 

charges have detonated, all fumes 

are clear, and it is safe to return to 

the blast area. In rare cases, the 

all-clear signal may not be given 

for hours or even days until the 

blaster can ensure that the blast 

area is safe.

3. The all-clear signal:

The three signals are described here:

This is important information for you! 

People have been seriously injured 

by flyrock.
U.S. Deptartment of Labor

Mine Safety and Health Administration

National Mine Health & Safety Academy

1301 Airport Road

Beaver WV 25813

e-mail: MSHADistributionCenter@DOL.gov

phone: (304) 256-3257

fax: (304) 256-3368

For information about occupational 

safety and health topics contact NIOSH at: 

1-800-35-NIOSH 

(1-800-356-4674)

fax: 513-533-8573

e-mail: pubstaft@cdc.gov

http://www.cdc.gov/niosh/mining

National Institute for Occupational Safety and Health

WARNING:

Blast Area

Delivering on the Nation’s promise:

Safety and health at work for all people

through research and prevention.

Photos and Drawing Credits:

 CDC NIOSH: R Mainiero, T Rehak 

 DOL MSHA: T Lobb, J Cottle

 PA Dept of Environmental Protection

 Flyrock Logos: Z Hubbard, E Schwartz

 Design/Layout: J Dickerson, M White, D Lawson

Under no circumstances should you try to see 

what is going on without the blaster’s permission. 

Contact the mine management if you have questions. 

Blasting is safe only if you follow the rules. Every 

day is different.

Don’t take blasting for granted!

This 1999 accident resulted in the death of a 34-

year-old miner at a Pennsylvania mine. He was 

sitting in this truck over the hill from the blast area, 

guarding the road that led to the blast site.

Visitor’s Hazard Alert

DE VOLADURA

D A N G E R

BLAST AREA

PELIGRO ZONA

Copies of this brochure can be obtained from:

Safer • Healthier • PeopleTM

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