We have done a great job of polluting this world. Over the years, industry has poured millions of gallons of pollution into our drinking water and rivers. And industrial smoke stacks have belched tons and tons of harmful materials into the air that we all need to breathe.

Most pollution was unintentional. From the beginning of the industrial revolution through the 1960s, many businesses simply did not know better. It was then common place for completely untreated, toxic industrial waste to be dumped into rivers and even oceans.

The now illegal practice of "dry-welling," where toxic chemicals were simply poured into holes dug into the ground, was legal, acceptable, and common.

The modern environmental movement really got underway in the 1970s and since then, the excuse of not knowing better has disappeared. However, a lot of harm already occurred before environmental awareness took root. And even now, legal and illegal dumping takes place on a wide scale.

All of this is not without a heavy cost. While there are many modern problems associated with our historic environmental sins, it is the impact on our health and well being that is of the most concern.

Prolonged exposure to toxic materials makes some people sick. Ranges of illness vary from moderate respiratory impairment to death. Yes, some people die as a result of environmental toxic exposure.

The kinds of illness vary greatly depending upon the chemicals in question, the concentration of exposure, the duration of exposure, and person-specific characteristics. An exposure that might kill one person, may barely affect another.

Since I am an environmental lawyer, potential clients frequently inform me that they believe that they have been exposed to environmental toxic substances and fear that either they are now, or will in the future become ill as a result of that exposure.

While these exposure claims are common, each person's claim must be individually evaluated. Unlike a task which entails a repetition of the exact same process over and over again, toxic exposure cases are extremely fact sensitive and are not amendable to a one size fits all approach.

The first question that I always ask involves the source and nature of the exposure. Is this a drinking water case involving pollution that has been discharged into the groundwater? Perhaps this is an air pollution case involving a local company's failure to prevent harmful chemicals from being released into the air through its smoke stack. Or perhaps this might be a case of contaminated material that decades ago was used as construction fill on a victim's property.

The next question concerns the identity of the injury producing chemicals. Are we talking about metals, such as lead, which are known to cause brain damage and other similar learning disabilities? Are we taking about certain solvents that are known to or suspected of causing leukemia and other cancers? Perhaps at issue are pesticides misapplied on property on which the victim works or resides.

An understanding of the chemical in question will inform us as to the concentration and duration of exposure necessary to make a person become ill. It will also inform us as to the kinds of illnesses associated with the chemicals in question.

From that information, we then must ask: whether the duration of exposure was long enough to make a person ill? Were the concentrations sufficient to make a person become ill? Are the complained of illnesses the kinds associated with the chemicals of concern?

In addition to the essential issues discussed above, we also need to know everything there is to know about the medical history of the victim. Has he or she had cancer before? Is there a family history of illness?

Does the person live or work in an environment where he or she is susceptible to other toxins that might explain the illness or contribute to the illness? Are there other unusual factors associated with this person's present or past lifestyle that must be understood to fully understand the case? And , is or was the victim a smoker?

I am also interested in the common sense components of a case. For example, if there has been a community wide exposure and many persons in the community seem to be similarly ill, then it is logical to conclude that there may be a cause and effect.

However, community wide exposure cases with only one victim force a question as to why a thousand people were impacted, and only one reports symptoms. This does not mean that the lone victim cannot or should not seek redress, but it does mean that a good answer to this question should be found.

Often, people have been exposed to toxic materials for substantial time periods but are not presently sick. In those cases, I strongly recommend consulting with an attorney to determine whether any action is necessary now in order to protect the victim's legal rights.

The biggest concern is that the statute of limitations, which establishes the time period by which a lawsuit must be filed, will expire long before an illness materializes. A lawyer who understands how these lawsuits are handled in the state in question will protect the victim's rights so that if illness does someday develop, he or she may still pursue legal redress.

In addition, some states enable a victim to obtain compensation for medical monitoring. This means that before illness develops, an exposure victim is entitled to the cost of visiting doctors and having appropriate preventative testing performed on a regular basis to ensure that illness does not develop, and if it does, catch it at the earliest possible time.

Neighborhoods all over the United States have experienced various kinds of toxic exposures. Fortunately, not every kind of exposure will result in injury. When illness does follow, or in cases where it is reasonable to fear that injury might occur at some future time, exposure victims should seek out appropriate medical and legal assistance.