In addition to the health and sanitation risks introduced by mice and rats, when they invade the job site or work facility, rodents can cause quite a bit of damage.
Rodents are capable of spreading diseases, like hantavirus and rat bite fever, that can be very harmful to humans. Infection is usually caused by the dust created when droppings, urine, or nesting materials are disturbed.
When mice or rats chew on cords and cables they can cause damage to the infrastructure, disable electrical systems and computers, and introduce fire hazard risks.
OSHA General Industry Standard 1910.141(a)(5) and Construction Standard 1926.51(h) Every enclosed workplace shall be so constructed, equipped, and maintained, so far as reasonably practicable, as to prevent the entrance or harborage of rodents, insects, and other vermin. A continuing and effective extermination program shall be instituted where their presence is detected.
The first signs of rodents usually appear before you ever see a rat or a mouse. During regular inspections of the work site be on the lookout for the classic signs of rodents: droppings and gnaw marks. Rodent droppings and gnaw marks are usually spotted out of plain sight in places like cabinets and drawers, or behind larger equipment.
To determine if rodents are a current problem, safely clean the area and then check back later. If fresh droppings are found, then you know there is an active rodent population that needs to be handled.
Hantavirus is transmitted to humans from the dried droppings, urine, and saliva of mice and rats. Hantavirus begins as a flu-like illness with fever, chills, and muscle aches, but if not treated promptly, it can rapidly progress to a life-threatening condition as the lungs fill with fluid leading to respiratory failure. Anyone working in rodent-infested buildings are at increased risk to hantavirus, particularly during dusty clean-up activities.
Rodents that are known to transmit hantavirus in the United States:
- Cotton Rat found in the Southeastern U.S.
- Deer Mouse found throughout the U.S.
- Rice Rat found in the Southeastern U.S.
- White-Footed Mouse found in Central, South, and Eastern U.S.
Rat Bite Fever (RBF) is a rare infection caused by a bacteria in rodents that can become life-threatening if left untreated. RBF can be transmitted to humans by bites, scratches, or contact with rodent urine or droppings. Symptoms of rat bite fever include fever, chills, rash, muscle aches, and joint pain.
There are certain work locations and activities that may increase the risk of illness transmitted by rodents.
Opening and cleaning previously unused buildings like storage facilities, garages, and sheds, especially in rural settings or after cold weather can put workers at risk. Rodents may have made a home in these closed-off areas and cleaning them out can stir up dust that workers can breathe in.
Workers can be exposed when they have to perform work activities in crawl spaces, under houses, or in vacant buildings that may have a rodent population.
Workers tasked with trapping rodents or cleaning up after a rodent infestation must take extra precautions and wear sufficient personal protective equipment to prevent infection.
If a rodent infestation at work is ignored, all workers in the area can be at risk. Any activity that puts workers in contact with rodent droppings, urine, saliva, or nesting materials is unsafe.
There are several ways rodents can spread disease to workers. When rodent urine, droppings, or nesting materials are stirred up, workers can become infected by airborne transmission. It may be possible to get sick if you touch something that has been contaminated with rodent urine, droppings, or saliva, and then touch your nose or mouth. People can become sick if they eat food contaminated by urine, droppings, or saliva from an infected rodent. Disease can be spread through a rodent bite or scratch. Rodents can carry ticks, mites, or fleas that can also spread diseases to workers.
To prevent rodent infestations at work it’s important to implement and follow good housekeeping practices on the job.
Store food, water, and garbage in heavy plastic or metal containers with tight-fitting lids. Do not keep any food at work that is not in a sealed container. Wash reusable dishes daily, including mugs, insulated thermos containers, and utensils.
Throw away trash at the end of your work shift that may have accumulated throughout the day, including food wrappers, used paper towels or tissues, beverage containers, etc. Use garbage cans and do not litter. Trash bins should be emptied regularly and not allowed to overflow. Trash should never be spilling onto the floor.
Near the building or work areas, cut back thick brush and keep grass short. Keep woodpiles away from the building. Seal up holes around the facility where mice or rats might enter.
If you see a mouse or a rat or notice signs or rodents like droppings in any work or common area, notify management immediately.
Because the inhalation of contaminated material is dangerous, clean-up procedures must be done in a way that limits the amount of airborne dust. Treat rodents or droppings as being potentially infected.
Anyone involved in rodent infestation cleaning should be wearing disposable protective clothing and gloves, rubber boots, and an N95 respirator. Additional protection may be required for areas with heavier accumulations of droppings.
Ventilate the space by opening doors and windows for at least 30 minutes before cleaning activities begin and keep the space ventilated while cleaning.
Dead rodents, nests, and droppings can be soaked thoroughly with a bleach solution or disinfectant and allowed to set for 5 minutes before cleaning. Disinfect everything that won’t be disposed of, like tools, materials, and work surfaces. Wear gloves, and wipe items with a cloth moistened with disinfectant.
Do not vacuum or sweep in a way that may create an airborne dust but instead clean with disposable mops or paper towels. Contaminated material, used protective clothing and equipment, and everything used during the cleaning process should be placed in a plastic bag and sealed for disposal. Thoroughly wash hands with soap and water after removing the gloves.