Copy of text from the Wikipedia site link posted
[edit] Health effectsAccording to the Agency for Toxic Substances and Disease Registry (ATSDR), eating food or drinking water contaminated with high levels of coal tar creosote may cause a burning in the mouth and throat, and stomach pains. ATSDR also states that brief direct contact with large amounts of coal tar creosote may result in a rash or severe irritation of the skin, chemical burns of the surfaces of the eyes, convulsions and mental confusion, kidney or liver problems, unconsciousness, and even death. Longer direct skin contact with low levels of creosote mixtures or their vapors can result in increased light sensitivity, damage to the cornea, and skin damage. Longer exposure to creosote vapors can cause irritation of the respiratory tract.
The International Agency for Research on Cancer (IARC) has determined that coal tar creosote is probably carcinogenic to humans, based on adequate animal evidence and limited human evidence. It is instructive to note that the animal testing relied upon by IARC involved the continuous application of creosote to the shaved skin of rodents. After weeks of creosote application, the animals developed cancerous skin lesions and in one test, lesions of the lung. The United States Environmental Protection Agency has stated that coal tar creosote is a probable human carcinogen based on both human and animal studies.[71] As such, the Federal Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 0.2 milligrams of coal tar creosote per cubic meter of air (0.2 mg/m3) in the workplace during an 8-hour day, and the Environmental Protection Agency (EPA) requires that spills or accidental releases into the environment of one pound (0.454 kg) or more of creosote be reported to them.[72]
There is no unique exposure pathway of children to creosote. Children exposed to creosote will probably experience the same health effects seen in adults exposed to creosote. It is unknown whether children differ from adults in their susceptibility to health effects from creosote.
A 2005 mortality study of creosote workers found no evidence supporting an increased risk of cancer death, as a result of exposure to creosote. Based on the findings of the largest mortality study to date of workers employed in creosote wood treating plants, there is no evidence that employment at creosote wood-treating plants or exposure to creosote-based preservatives was associated with any significant mortality increase from either site-specific cancers or non-malignant diseases. The study consisted of 2,179 employees at eleven plants in the United States where wood was treated with creosote preservatives. Some workers began work in the 1940s to 1950s. The observation period of the study covered 1979- 2001. The average length of employment was 12.5 years. One third of the study subjects were employed for over 15 years.[73]
The largest health effect of creosote is deaths caused by residential fires.[74]
You guys can use whatever you want that makes you feel safe. I personally would have no problem using cross ties to make a raised bed garden. If you are considering pressure treated lumber, look at the special handling requirements in the MSDS on it, to name a few, wear gloves when handling to avoid skin contact, wear eye and respirator protection when cutting to avoid inhalation of vapors in the sawdust. The stuff used is TOXIC but most people dont read or even think about it.
In my case, I used left over bricks for my raised flower bed and rocks removed from the construction of the foundation and dug from the yard to make the vegetable bed since they were available and free and looked pretty when finished.
Just remember that someone pays for research in most cases it is the gov. but sometime private funded and they are going to make their report to favor the opinion of the funding agency. If it is the EPA, they want to ban everything. Look at the parameters of the EPA testing in the Wiki link for making the poor rats get cancerous lesions, shave the skin and apply creosote everyday for weeks. Proper handling precautions are necessary for all products including water. Ever look up how many people have died from water poisoning and I dont mean contaminated water. TOO MUCH of anything including water will kill you. Use good practices in handling materials and you stand a beter than average chance of living a long and healthy life.